What is the centre hole for in modern train tracks?

The larger hole is present in older 9V track as well:

I've never actually done this, but I've always assumed that the hole is there so that the track can be screwed or nailed down if desired to create a semi-permanent layout. This is common practice with traditional model railroad track:


Bluetooth communication between computer and nxt using RobotC

It's possible. simply make a BT connection and then use the control interface from your computer


Have you tried horizontal clips? They will be a little taller than 1 plate in the center, but you might be able to adapt them to your needs given that the connection point is just one plate. Perhaps these parts:

60470b

48336

Something like 4623 with a vertical clip might also be a possibility depending on your constraints:


Where did these small tan bricks come from?

These look like Modulex bricks:

Modulex was a building system that was designed for adults. It was developed by The LEGO Group at the same time as their Modulex sets were produced from 1963 until 1965, and were exclusively available in parts packs by colour. The LEGO Group made Modulex a separate company in 1965, and the text "LEGO" was removed from the studs and replaced with "M".
Modulex bricks were formed with a cube type 5 to 5 width/length ratio, meaning that, unlike very nearly every product produced by The LEGO Group, they were not compatible with LEGO bricks, which have a 6.5 to 5 width/length ratio. Modulex bricks were available in a wide array of unusual colours, shapes, and sizes.
from Brickipedia


I have the same problem with mine.
Some time ago I had a really bad battery leak, and with some perseverance I managed to clean up the majority of the corrosion using distilled water, white vinegar and a mountain of cotton buds!
Unfortunately, I lost my speaker (The plastic, and thin cables completely destroyed)and I suspect some damage to the contacts along the edge of my LCD occurred.
What I find now, is that my LCD in general doesn't work, and IF my unit has been switched off for an extended length of time, I have to get a fresh set of AA batteries (All 6) pop them in, and plug the USB cable in, then just leave it sitting there connected to the PC for about 4 hours, after which I open my computers device manager, press the power key and usually see the device manager spring to life.
If the batteries are good, I might get some flickers of graphic on the display, but for the most part the display is effectively useless, however if your happy to open your unit up and not afraid of electronics, then some isotropic alcohol and a non fibrous micro cloth (Such as a glasses lens cloth) can be used to clean the rubber contacts around the edge of the LCD (Mine had 0 output until I did this, and only then did I start getting some flickers of activity)
It does seem to be a common problem too, judging by the amount of units for sale on eBay with non working displays for spares or repair...


Can someone identify this LEGO Model? Brown Technic set with huge dark grey wheels?

It's set 4481 - Hailfire Droid. You've got it tilted vertically, it needs to rotate 90 degrees - the black rocket launch pods need to be on top.


Need help identifying extra large Lego figure from 2003

48379 is the part number for the torso piece. 2003 would be the copyright date for the LEGO trademark.

They are both promotional items which were distributed with McDonald's Happy Meals.

Bricklink: 7923-1 (White Soccer Player #4)

Bricklink: 7917-1 (Blue Basketball Player #22)


This guide here (off-site backup) in the BrickJournal magazine has a section titled "Step Three: Protecting Your New Figure – Application of a clear top coat". It recommends Future’s floor wax or Badger overcoats and discourages the use of nail polish due to its tendency to yellow when exposed to sunlight.
They suggest applying two layers, each dried with a hair dryer to achieve a smooth, bubble-free surface.
Admittedly, these instructions are for display models, not figures that are going to endure the wear during play or everyday carrying along several keys, but these layers can be reapplied when they are damaged and will protect the figure and its paint while the overcoat is intact.


From your description, it seems you use a motor block which just tells the motor to start running. This works, but since your program then comes at an end, all motor activities are stopped immediately.

To solve this, you have to make sure your program doesn't terminate immediately. You could either use a wait block, with a fixed timer after which the program (and motors) will stop, or maybe a block to wait for another condition to happen (button pressed, sensor activated, number of rotations reached,...).

Another solution would be to change your motor block and use a "move" block - which instructs a motor to move for a certain time (the block wait for that time to be completed).

Keep in mind this is all from memory though, I may be wrong on the particulars; but in essence I'm confident your problem is due to your program terminating immediately.


Is it possible to connect EV3 and NXT bricks like master/slave configuration via bluetooth?

There are many possible ways of doing this. I am a contributor to the ev3dev project, so I am a bit biased in that direction.

To do this with ev3dev, I would install the nxt-python package on the EV3 and use it to remote control the NXT.

If you want to stick with the standard firmware, another possibility would be to relay bluetooth mailbox messages through a PC or other device. Here is an example (it goes in the other direction though - NXT controlling EV3).

Another possibility is to use Lejos or MonoBrick. Both have NXT and EV3 remote control libraries,


The ideal frame rate is 24 fps due to the brain holding an image for .051... seconds

However in stop motion animation this can be quite tedious and time consuming.

So with that in mind I'd recommend a frame rate of between 15 and 18.

As for your ideas on making money out of it, I'd say go for it.


Bugatti Chiron - loose connection to wheels

I see a gap between the grey part and the black part. They should be flush picture 1. Normally it take some force to assemble these hub parts.

If you look to the back side of the "back" side you must see the clip of the grey as
picture 2.

The grey part must rotate freely so if you apply some force to if and have it slow down if its own it must continue to rotate for some seconds until it stops


What's an effective strategy for purchasing large numbers of different bricks?

On bricklink, your example, if you input the parts into a wanted list it allows you to find stores that have all (or most) of the parts on the list letting you minimize shipping costs.


Help identify this non-LEGO set - curvy slopes and stickers

This looks very much like the rear end of set 8669 Fire Spinner 360:

Only differences being that the pieces are counterfeit and the red on the stickers has been replaced with green. This is therefore, presumably, from a clone-brand version of this set.


How to stop or freeze the EV3 large motor in position

According to the official documentation you could use
hold()

which

Stops the motor and actively holds it at its current angle.

Note: My assumption here is that you are referring to this

as "large motor". If you are using a PF Large Motor:

then this advice is useless, as those can't be controlled with such precision due to the lack of an internal rotation sensor.


How much does a life sized LEGO person sculpture weigh?

The image posted in your question shows the Lego brick artist Nathan Sawaya.

On his website, he states:

  A life-size human form sculpture typically has 15,000-25,000 bricks.

So, lets use 20,000 for our calculations.

Next, how much does a brick weigh, well of course it depends on the type of brick, but if we take the common 2 x 4 Brick , Bricklink tells us that one 2 x 4 Brick weighs 2.32g.

20,000 x 2.32 = 46,400g
= 46.4Kg
= 102.3Lb
= 7.3 Stone

So one could say they are very roughly equivalent in weight.

But if anything, the Lego versions are likely lighter than their human twins. This is especially true if we consider that many of the bricks will be smaller than the 2 x 4 Brick we used in the rough calculation above. For example, according to Bricklink, the 2 x 3 Brick weighs 1.92g and the 2 x 2 Brick weighs 1.21g.


Do LEGO part counts on boxes include spare parts, brick separators and instruction manuals?

No. Set 30476 (pictured below) says it contains 33 pieces, but the set contains 3 extra pieces in addition to the ones needed to build the set. I believe it has always been this way.
Yes. When LEGO re-released the Taj Mahal, it contained exactly the same pieces except for the addition of a brick separator. The part count on the set's box was also increased by 1.
No, excluding the extra pieces, 30476 (pictured below) has exactly the 33 plastic pieces the manual says it should have.

Set 30476:


What does 191767 mean in "Paper, Cardboard for Set 4336 #1, Scala Cat (191767)"

My guess would be that it is the LEGO element ID (6-7 digits as far as my observation goes). This is different from the item number which is shown on the bricks or on BrickLink. The item number usually contains (or is equal to) the design number.

Example: I have a 2x6 plate in tan. This shows the number 3795. As this is a common piece I looked it up on the LEGO website (search by design number) and this reveals that the element ID (which also contains color information) is 4113993. Some element IDs contain the design number as well, e.g. 379501 is the very same plate in white.

Unfortunately the piece in question seems to be rather old, so I could not find any information about it online. (And to find element IDs is a challange by itself as they seem to be "LEGO internal".)


Does the PF Servo motor return to center?

Here is another video from Sariel which shows that it returns to center: http://www.youtube.com/watch?v=T_Gvuzsngg8

With the 58122c01 Remote Control Unit it returns to center if the remote is not actuated.
With the 64227 IR Speed Remote Control Unit  it returns to central position when the stop button is pressed.


Emerald Night Piston replacement + jamming issue

There is a Bricklink store that sells custom-made train driver rods. I've never bought any so I can't speak to the quality. There are supposedly limitless varieties possible but given that you're looking for one that matches a set you should be able to find some already-made for that set.

Regarding the jamming issue, the most common problem is when the wheels aren't properly quartered. When building, the pin holes for the pistons on one side should be at 12:00 (top) and on the other side at 3:00 (front). This helps prevent jamming.


Why won't the loop block in my EV3 program stop?

Your code instructs the motor to continuously turn in one direction, and because you chose a motor block in the “on” mode, it will continue to turn even during the loop condition check. The loop condition says the loop will continue as long as the button is released (AFAIK, I don’t have an EV3 close by currently to validate this), which means that it does exactly the opposite of what you intended. Change the loop condition to loop as long as the touch sensor is pressed and you will fix this issue. Plus, once the loop finishes, the motor will still continue to turn; you would need to put a Motor block in the “off” mode directly after the loop.


How to convert new 4x4 crawler to tracks?

I started with something based around the tracks that came with the original LEGO Mindstorm's kit: 680 Technic Tread:

I then build a rather more bulky than I'd have liked set of beams around it - I think if I'd have really dug out my Technic elements I'd have had more success making it look closer to the mattracks options:

Here's the very bulky rear - this would obviously want to be pared down somewhat, and you might want to either power the top wheel, or both the bottom ones:

Here's the rear with the beams removed:

You would need to have the driving axle on a universal joint to allow cornering, and would want to mount the whole thing on the mounts for steering.

I think it would be better if I'd had more of the newer Technic beams (the ones without the studs - I could have then connected them with two coat-hanger pieces and have another one vertically to the top.


There aren't many sets with big Bionicle part variety. I'm not sure what you are looking for. If you need specific parts I suggest to look for them on Bricklink. If you need to increase your Bionicle parts collection it might be better to look for local sales as Bionicle/Hero Factory are usually quite cheap.


Repairing Lego minifigure torso cracks/damage

one thing that worked for me is to use a very small needle-nose plier or a tweezer to hold the torso from inside while pushing the crack apart (very carefully). now you can use a toothpick or a needle get a bit of superglue in the crack to fix it.

note that this just works for bigger cracks like the ones going up to the armpits.


Distance Learning Mindstorms web-based software

Here's Microsoft Makecode. It is full of tutorials for the EV3, such as:

• Example programs

• How certain sensors work

• How certain code blocks work

• Instructions for EV3 robots

• And much more.

Is this what you're looking for?


Since none of us here officially represents The Lego Company, the only possible answer at this moment (if I take your question literally) is "no". We don't know whether TLC has introduced a change in the manufacturing process, if such a modification was made in order to reduce costs, and if such a modification could have resulted in sub-par quality bricks.

The phenomenon you describe can be a result of a deliberate modification in the production process, an honest accidental mistake at one of the manufacturing facilities, or even might be a textbook case of confirmation bias, and it is quite hard to differentiate between these without auditing the relevant factories and your experiences.

The only ones capable of giving an official answer would be the customer support team at Lego, but I guess they would just tell you that they strive to provide their valued customers with the highest quality bricks, and they sorry, but they can't disclose exact manufacturing steps or financial decisions. But they might offer to replace your cracked bricks, or at least might appreciate feedback, so I think you should write them a detailed message about your experience.


Based on this API reference and this discussion of the color sensor it looks like "pct" is short for percent as in a ratio with 100.

David added in a comment:

  EV3 hardware developer kit provides a bit more info on what 100% means:

    The output from the sensor within light sensor mode is a value between 0 – 100 where 0 equals no reflected light measured and 100 equals full light reflection.


Please help identify the LEGO set from picture


It's most likely that this is not an official Lego set. There has been such a piece (the purple ones) but it never came in that color, therefore it must have been manufactured from a clone brand. There could be that 00.1% chance of it being a piece from an official Lego set, but based on the poor quality of the build in the image and the fact that Bricklink couldn't find it, I still think it's from a clone brand. Also, if any of the plates have only specific studs with holes in them that aren't in a reasonable pattern (such as outline of house walls), then there's a big chance that the plate came from Mega Blocks and not Lego™.


How do the 61927 actuators work in MK II crane set (42009)?

THe actuators both turn in the same direction, as there is a gearing “bridge” between the two axles driving the actuators that consists of 3 interlocking gears. 3 gears that interlock cause the 2 outermost gears to spin in the same direction. You can easily validate this with a small test setup using a Technic brick with holes, a small axl and a few gears and axle pins.

EDIT: For clarity, this picture shows how each of the key gears spin in this setup.

The two flat bevel gears marked with #1 spin in opposite directions from eachother, but this is possible because even though they are on the same axle (#2), they are not attached to this axle as the gears have a pinhole, not an axle hole, and hence they can spin freely (see part 87407 on Bricklink). It is likely gear #3 (marked in yellow) that is the gear that is driven, and its power and rotation is transfered to its twin gear which drives the other actuator (and spins in the same direction).


How to disassemble this small Technic turntable, combination of parts 99009 and 99010?

These parts do not come apart. They are designed to be clicked into place and then remain connected. I have not found nor heard of a way that these can be separated without damaging the plastic and hence the functioning of the part.

The assembled component has part number 99009c01 - Technic Turntable Small, Complete Assembly with Black Outside Gear Section.


You could cross-check the sets with the transparent 1 x 4 tile and the transparent 1 x 2 plate. No matches jump out at me.

Unfortunately, I don't know of any tools to make crosschecking easier.


There has been a staggering amount of different size and shape LEGO buckets, tubs and boxes. A lot of them are stackable with each other (meaning the same size and shape box produced at the same time can be stacked). I think narowing down the question would be helpful. Are you looking for LEGO boxes currently in production? Or all boxes LEGO ever produced? I just did a quick search on Bricklink and over 300 results came up just for LEGO buckets (similar to the ones you are picturing above): http://www.bricklink.com/catalogList.asp?pg=1&q=bucket&catLike=W It would be huge work to try to work out the compatibility of all of them.


Can you please identify these two assemblies, dark grey, dark red, yellow, and tan plus Technic treads with large orange pieces?

In the top image you have parts of 7656-1: General Grievous Starfighter and
7669-1: Anakin's Jedi Starfighter.

In the second image you have parts of
7706-1: Mobile Defense Tank


How to lubricate the 4.5v train motor for set 7722?

Undo the 2 screws at the top and then take of the top cover.
You can now take the actual motor out  of the casing. It just sits loose in there.
Then you can undo the 2 screws in the bottom to free the metal block with the plastic gears.
It is most likely those gears that cause the squealing because of dust/dirt that got into them.

I would recommend to clean them first using a soft brush. (Paint-brush works well). You can stick an axle through the bushings and turn the gears manually or rotate the big gear shown at the top with your finger. Just let the gears run against the tip of the brush.
Don't stick the brush in too deep! You don't want the hairs of the brush to get caught in the gears!

Then lubricate with a little bit (a few drops is enough) of plastic safe oil. the movement of the gears will spread the oil around eventually when the whole thing has been put back together and is running again. (This might take some minutes of running though. Don't expect the noise to go down after 5 seconds!)

Don't use WD-40. It will degrade the plastic !!!

You should NOT lubricate the actual motor itself. Some of the oil you put on the gears will eventually make it into the electric motor and that should be enough.


Is there a way to keep large plates together more efficiently?

This isn't my personal experience, but I have seen and heard people use rubber hammers for fixing larger plates onto baseplates, which shouldn't be all too different from fixing them onto normal plates.

Those are a classic homeworking tool, commonly used pretty much for the "real world" equivalent of what you're doing, fixing floor tiles and cobblestones into place. They should be soft enough when applying force over a flat area as long as you don't hammer away like a madman. For additional protection you could possibly also put a piece of cloth over the plates. It's probably still more effective and lesss straining than using your hands to hammer or your thumbs to press.

In general though, it's also not a bad idea to try and avoid sticking too many big plates onto each other, as even if you get them pressed together really tightly, it can lead to bending of the entire model when done over a larger area, which is especially noticeable when having a flat ground stand that then...isn't flat anymore. Some of the "thicker" Architecture sets like Trafalgar Square or Robie House exhibit this problem. Try to thin it out when you can or use baseplates for the bottom layer, which are a lot more flexible in themselves.


What is an inexpensive camera for photographing LEGO?

Lighting is key for any camera, but especially for the sensors in cell phones, tablets, and inexpensive point and shoots.

If you place your LEGOs in daylight or under a bright white LED / CFL you may find your iPad will do just fine.   Whereas, under normal room lighting the photos become a noisy mess.


The 75192 Millenium Falcon is available again!

Can it be sold out within one hour?

Probably. If they sell all they have available, it would be "temporarily not available" again.

This set has been known to sell out the same day it becomes available in other countries.


Is there an .lxf file resource of production Lego sets?

The Eurobricks forum has a topic dedicated to user created LDD files of existing LEGO sets.

There are currently four different versions of the #10179 Millennium Falcon made by different users:

yellost (23 August 2010)
bbqqq (12 November 2010)
Calabar (20 October 2012)
kcoon (16 December 2013)

There is also a topic for official LEGO sets re-created in ldraw.


Help identifying this 1x1 2/3 brick (no studs)

I believe that you are seeing the wide end of a cheese slope like this:

Note that these are simply held in place by friction and not really "connected" in a traditional way.


It is very common for Lego to pack larger parts like Plate 2 x 16 not in a seperate bag, for sets this size.

If I look at the inventory of set 7155, and compare this with sets I built over the years, I think 3 bags for the parts could be correct:

bag with minifig parts and small parts like 1x1's and 1x2's;
bag with large size parts like the 4x8 plates;
bag with remaining parts.


Does someone know this tire's origin? What set contains this piece?

It's Part #32197 - Wheel 81.6 x 34 ZR Three Spoke Swirl. made only for one set.

Set #8448 - Super Street Sensation.


What solutions are there to organising a LUGBULK order?

For our Lug, we have assigned one person who is the contact for all things LUGBULK and is also responsible for the organization of everything. (He also happens to be the one who will spend the most).  We followed this general format to keep everything organized.

At the most recent club meeting, we agreed on those parts that the club needed for upcoming projects. These get the highest priority.
Once we received notice of LB2013, we asked all of the members to submit their information needed to register and to get an accurate count for Lego.  We gave our members 10 days to get this in.
Within 5 days, each member was allowed to submit up to 10 part requests in order of priority.  Each member is also required to submit the ElementID along with each part in order to make things easier.
The person in charge of LUGBULK for us merged everything together and removed any duplicates.  If we were over our maximum of 100 elements on the wishlist, things get removed that were likely to be declined, or that would be cheaper on BrickLink or PAB.
The wishlist is submitted to Lego.
Once the approved list and prices are returned to us, we create an excel sheet of available elements and add in columns for BrickLink color names and current BrickLink prices and send it to all members.
All members are required to send in their orders within 7 days.
The coordinator merges together the orders and sends to Lego.
Once the LUGBULK order is received (on a pallette :) ), the coordinator pays Lego directly, divvies up the orders (or we have a sort party to do it) and then each member pays the coordinator.


How should I remove a Hinge Tile, especially in the middle of a plate?

Often in these cases, I have been able to flex the plate the piece is on a little.  This allows you to get a fingernail or small tool under the lip of the thing in the middle of the larger plate.  If you don't flex too much, you won't do any permanent damage to it.


Are all of these police minifigs from LEGO?

As pointed out by others, the first three minifigures are genuine LEGO (with the second having perhaps a few custom accessories). The fourth is not a LEGO minifig. It may include some genuine LEGO elements (legs, hands, etc), but the militaristic accessories are not LEGO elements. This appears to be a custom minifig sold at one time by Modern Brick Warfare.

Not only does LEGO not include guns in their City sets, they also have much better lighting for their minifig photos than this.


Rebuilding the Millennium Falcon 7965 with unsorted bricks?

Only ever throw out LEGO that has sustained actually irreversible damage, bricks that have been bent beyond repair or snapped. It so rarely happens that I can find a suitable picture. In this case, I would assume the longest plates and tiles would be more likely to be damaged.

I'd go through the painful process of dismantling the model and starting again, replacing any broken pieces (if any) or at least starting again from the last significant building stage. Many large models are build independently and combined at a later stage of building. These independent 'building stages' often match a numbered set of plastic bags.


As far as I know, it's not intended to have any building function, it's just there to prevent any excess plastic at the fill hole from getting in the way of other pieces.

I can't find a good close-up picture, but that particular piece is filled through a hole in the mold at that location, which you can kinda see in this picture.

Without the small recess, if the sprue were to leave behind a small nub, it could prevent sticking the piece next to another piece.


You can do it using EV3 Bluetooth blocks.
You can send integers, string or boolean using different "mailboxes" so the receiver just need to use the Block to read from a particular mailbox to get the data.

Maybe I write a post where I detail all this more because LEGO documentation isn't helpful at all.


Donny Chen made a LEGO piano that I believe is just large enough to play. Details are available on LEGO Ideas. You can watch him show it off in a video from Brickvention 2019. He has it motorized in that video.

From your comments, it sounds like you are interested in not simply having a piano with keys that can move, but one that actually emits proper sound. I think it will be quite difficult to do that effectively using LEGO elements (string, rubber bands, etc). The best that you can probably do to deliver sound using LEGO elements would probably be using EV3 or BOOST. This would be similar to the guitar model from the BOOST set:


How to verify authenticity of smaller LEGO parts?

I have many 1*1*2/3 slope

On this piece the LEGO marking should be seen on the flat, semicircular part on the bottom:

  Dark green - 3 with no number, n.o 31, n.o 3, n.o 5

I'm sorry, but I can't identify this piece, a photo would be helpful here.

  Red/brown - n.o 29, 2 with n.o 15.

Just like here

  Trans orange and red - 8 with different or no n.o

Or here.

  Also with the 1*1 round brick and nose cone - are there ANY markings usually?

Yes, there are, but they are quite tricky to find. On the 1x1 round, you should be able find the marking on the inner side of the top ring, facing down:

While on the cone, it is similarly on the underside of the flat ring, but close to the bottom, so easier to see:

  Also with the weapons and tools - I have many with a (C) but some with nothing...

These are quite broad categories, so if you have any specific pieces, I'd love to help you :)


Why is my LDD model incomplete after I export it to LDraw?

This in not a LDView problem, but a conversion issue between LDD and LDraw. Only parts present in both libraries will be displayed. Moreover, the file (ldraw.xml) that defines the correspondance between parts of both systems must be up to date. Latest version of this mapping file is available here.


Can you change the sensitivity of an EV3 Touch Sensor?

It is not possible to increase the sensitivity of the touch sensor in-programming. Generally, you can use a lever to decrease the amount of force required.

Here the "load" is the touch sensor button, the "effort" is the ball hitting the lever, and the beam is a lego beam.

If the ball you're using is too light, you still probably won't be able to depress the touch sensor, regardless of how long the lever is. You can experiment with a heavier ball and a lever arm to try to get it working.

If you can't get a mechanical solution working, or if it is required that the ball is only detected when it hits a small target, a light/color sensor might be the next thing to try.

Side note, I think it's really great you're helping your son with his project. Feel free to post back here if you have more questions!


How should I model a Heroica scale castle bedroom?

Here is my attempt on a 6x6 plate. I built only one wall for the image clarity, but maybe you'd prefer one opposite wall as well.

If you don't have the tile with the pillow, replace it with a 1 x 2 slope or something.

Construction details if it's not clear enough:


What set are these LEGO assemblies from?

Set 75013 Umbaran MHC (Mobile Heavy Cannon) , based on the leg shape and the Dark Red 1x1 Headlight Bricks.


Can I change the Bluetooth identifier for an EV3 brick?

I'm teaching an after school robotics program and the kids are using the LEGO MindStorms Education Core Set #45544. I was dealing with the same situation when I had to connect 10 EV3s to Bluetooth or Wi-Fi and I couldn't distinguish from one EV3 to the next.  Anyhow, I figured out how easy it was to give each brick it's own unique identifying name. You want to make sure that the EV3 is connected to the computers via USB cable and that the LEGO MindStorms program is opened. In the bottom right corner of the screen, you'll see the hardware page. Click on the brick info and then just change the name.  See image below.


Where can I find details/instructions for this keychain?

While searching on Bricklink I've found two items that are related to minifigure in question. All I could find is some picture and minor details of this minifigure flashlight key chain here.
As we can see on picture below one of two of the items I've located on Bricklink are present in this bundle. For some reason items in Bricklink's catalog share similar part ID (UT21222-1 and UT21222-2, where "-number" is used to distinguish items with same part ID), while KAI has entirely different picture. It is unclear if picture used on Bricklink is incorrect or Kai's print has changed at some point.

Some details from shared website (in German):

Art.Nr.   3017.21222
Hersteller Nr.    UT21222
EAN-Code  4041268212220

Schlüsselanhänger mit Taschenlampe im Lego Ninjago Design inkl. Batterien im Display Hiermit stehen Sie nicht länger im Dunkeln. Durch die beweglichen Beine kann gleichzeitig in zwei Richtungen geleuchtet werden. Im Lieferumfang sind bereits zwei Knopfzellen (Typ CR2025 3V) enthalten, welche bei Bedarf ausgewechselt werden können. ACHTUNG! Nicht geeignet für Kinder unter 36 Monaten. Enthält verschluckbare Kleinteile. Erstickungsgefahr!

And with a help of Google Translate in English:

Keyring with torch in Lego Ninjago design incl. Batteries in the display With this you are no longer in the dark. The movable legs can be used to illuminate in two directions at the same time. The scope of delivery already includes two button cells (type CR2025 3V), which can be exchanged if necessary. ATTENTION! Not suitable for children under 36 months. Contains small parts that could be swallowed. Suffocation hazard!

Unfortunately, I think LEGO does not keep/provide any online instructions for this accessory.


Technic Pin/Travis Brick Legal Connection?

In general, this sort of connection is illegal, but I think that it works fine with a Travis brick. Technic pins must be "in click" in a model, or the pins will be held in compression and can be damaged over time.

Here's a slide from Jamie Barard's classic "Stressing the Elements" presentation that explain the need to have Technic pins in click:

And here's the slide that explicitly states that Technic pins should not be used to connect to System bricks:

Here's an example of a set that didn't keep Technic pins in click and the resulting damage from prolonged storage assembled:

With all of that said, the four holes that run through the stud connections on the sides of a Travis brick provide ample room for a pin to click into it. This isn't an obvious connection as with a Technic brick, but the fact the pin can move freely inside the brick indicates that it isn't in compression and is simply constrained to remain inside.

I can't speak to whether or not this type of connection would get through a design review today, but I can say with confidence that this wouldn't cause damage to elements. If this is considered "illegal" it would be for other reasons.


The Travis Brick is the 1×1 brick with studs on four sides.

The nickname arose amongst LEGO Space builders. It was nicknamed The Travis after talented Space builder Travis Kunce. He liked the part so much he had a tattoo of it.

The brick is especially useful in SNOT techniques as it has studs on all but the bottom surface.


If you already have a specific set in mind BrickSet provides links to ebay, bricklink, etc. to get a good overall idea of what prices look like.  BrickSet also has a tag for pneumatic sets.  I use it for tracking my wish list and what I already have.

I usually end up buying the sets or parts on BrickLink, but I'm not shopping for old sets that often.  There is much less sketchy stuff happening in BrickLink than on ebay.  You can find better prices if you're patient with ebay, but the BrickLink prices are often totally reasonable.  BrickLink also functions as the canonical list of sets and which parts are in which sets.  Sites like BrickSet automatically synchronize with it.

Looking at one of the oldest pneumatic sets - 8851 Excavator - ebay has it for $12 & $12.99.  BrickLink's prices start at at $39.67 so I'd probably see if the ebay seller's have high-enough ebay reputation to deal with.  In this case ebay might even require less patience than bricklink.


At certain times of the year (particularly at the start of the new year) LEGO release new sets and at the same time remove older sets from their inventory.

Also, in November and December in the run up to Christmas LEGO investors may take advantage of the increased demand by raising prices. Parents buying presents for their children would perhaps bid higher than usual as they are keen to get the right present and in time for Christmas.


This modification won't change the rate of reduction.

You can calculate the ratio of the angular velocities of two adjacent gearwheels as

i12 = w2/w1 = n1/n2

where w is the angular velocity and n is the number of teeth of the gears. Hence the original reduction reads as:

i12*i23*i34*i45*i56 = 12/20 * 16/16 * 20/28 * 12/20 * 12/20 = 27/175 = 0.1543

while the modified is:

i12*i23*i34*i45 = 12/20 * 12/20 * 20/28 * 12/20 = 27/175 = 0.1543

What you did is you simply removed the 16/16 and replaced the 12/20 gears, which results in the same reduction because the order of the multiplication is arbitrary.

To the second question:

You can change the 12-20 gears to 16-24 ones to fit the increased distance. In this case, the new reduction is

i12*i23*i34*i45 = 16/24 * 12/20 * 20/28 * 12/20 = 6/35 = 0.1714

Note that the new gears may intersect parts not shown in the figures.


How to fill a vertical 1.5 stud wide gap?

Before I attempt to come up with an answer, let me share how I think through problems like this, as it might make it easier for others to solve problems like this in the future.
We can see that the gap itself is 30 LDU, as modules are 20 LDU, so 1.5 modules is 30 LDU. Some quick rules of thumb:

Multiples of 20 LDU can be made with regular bricks horizontally
Multiples of 8 LDU can be made with bricks, plates, and tiles vertically
Multiples of 4 LDU can be made with clever use of brackets and Erling bricks
Other numbers require the use of fairly odd pieces

We see that 30 LDU is not a multiple of 20, 8, or 4, so we'll need some special pieces for this. If we had an element that was 6 LDU thick, we could then make up the difference using 3 plates (30LDU - 6LDU = 24LDU = 8LDU * 3) or one brick vertically. Thankfully, at least one such element exists in the classic fences:

We can stack 3 plates or one brick on the center section to perfectly fill our 30 LDU gap:


What is the largest jump in LEGO instructions?

Car Chassis 8860 gets my vote for complexity of a single step.

The instructions are laid out so that you have two pages like this on top of each other.  I was building this model with my 11 year old son recently, and at almost every step on the last couple of pages we found we had missed something from the previous step.


Are these LEGO Star Wars bricks genuine or fake?

I can't find an official source for this statement, but with the exclusion of a few rarities like test bricks, and perhaps a few other cases, every piece of genuine LEGO will have the brand stamped on it somewhere.

You've taken photos of pieces together that clearly ought to have come from the same mold, where one displays the LEGO brand and the other does not. That seems like solid proof that you've purchased fake parts to me.

As an example of how similar clone bricks can be, here are some battle droids made by LEPIN: https://cheap-bricks.com/lepin-05025-star-wars-homing-spider-droid/

It's hard to see, but I can make out the © on the trigger of the stormtrooper's weapon.


How is the corner on Azuma Makoto's LEGO bonsai tree done?

The two corners of the bonsai tray shown in this image appear to be built differently...  I've chosen to do the technique shown on the left.

The best I could do was use various lengths of two-wide bricks and staggered them in a upside-down pyramid shape with 2x2 bricks in the corner.

I was trying to re-create the model from memory, and I forgot to add another row of staggered plates.


Arranging claws radially and horizontally

Your claws will fit in this Technic element:

https://www.bricklink.com/v2/catalog/catalogitem.page?P=10288


I can't figure out which lego model these doors came from

UPDATED LISTING THE CORRECT STOCKADE DOOR - Thanks to TheBrickBlogger

The two left doors are 30223 - Door 1x5x7 1/2 Stockade and they appear in 11 sets.

The middle one on your picture seems to be Reddish Brown, which is in only 1 set, 7036 - Dwarves' Mine, exactly decorated the way you have the door (with the pyramid shape in Pearl Gold on top).

The left one is the same door in black; there are 5 sets with this door. None of the doors visible on the pictures in Bricklink is exactly as you have it - so likely it was used by the previous owner in a MOC, unless it is one of the not-clearly-visible doors in 7419 - Dragon Fortress, which has 4 of these doors in the set (all other sets have 2).

None of the sets that these doors contain the net, but out of the 46 sets with a 71155 - String, Net 10x10 square there is only one where the net is folded double and squeezed between the 1x4 plates on your picture.

This particular set is 7048 - Troll Warship and you see the net being used in exactly the same way to trap a minifig, so my best bet is that this net comes from this set.

The sets I describe here are all from the period 2003-2008, so that would have been the previous owner's key years of LEGO collecting.


Can anyone identify these 4? (Extra 1x3 brick for scale)

These are Part bb300 Garage Door Counterweight - Old without Hinge Pin

from Part # 822ac02 - Garage Door Solid Assembly - Old (Hinge Pins on Counterweights - Both Sides)

which belongs to

Set #435-2: Garage Plate and Door (The Building Toy)


Comparing LEGO® MINDSTORMS® Education EV3 Core Set with LEGO MINDSTORMS EV3 Toy Robot Building Kit - 31313

Here is a parts list for  the CORE SET: https://brickset.com/sets/45544-1/Education-EV3-Core-Set
And here is a parts list for the Toy Robot Building Kit: https://brickset.com/sets/31313-1/Mindstorms-EV3
In the future, there is a good chance that Brickset has an inventory!


I am doing research for this answer from time to time and this answer is going to be updated as I learn new things. Feel free to suggest edits or post your own answer if you have better information.

Problems

There are five problems that need to be solved when looking for a replacement rubber band:

Diameter

(image source)

This is probably the easiest. There are a lot of rubber bands available in every corner of the Internet and for most cases you'll likely be okay with slight variation in size.

Height

Height being how tall the band is when you lie it down - too tall and it won't fit on bushes or wedge belts. Sometimes seller will specify this dimension, if not you can always try asking.

Thickness

For most intents and purposes thickness should not matter much, unless you're dealing with severely limited space which in my experience is rarely an issue with official sets.

Cross-section

LEGO rubber bands come in two cross-sections - square/rectangle and circle. While I've found countless square/rectangle rubber bands I'm yet to find a single seller who deals with round. Even on Aliexpress which is said to have everything available.

Unless you're lucky you'll have to manage with square ones.

Tensile strenght & stretchability

LEGO sets rarely deal with forces sufficient to snap a rubber band, though how much energy is required to stretch it might be important. That's not an easily found information, so you have to deal with it by either contact the seller (or even better manufacturer), or buying different kinds and trying them out.

Solution

Even though the question is about finding alternatives, your first line of action should be seeing if the official ones are available.

Check on Bricklink and other LEGO marketplaces if the specific rubber band you're looking for is available in an acceptable price. Just remember that rubber bands from very old sets even in mint condition can be weakened by old age.
There is an official rubber band pack from LEGO (2000707-1) which can be fairly easily found but it's not cheap. There are likely other sets. Make sure to email LEGO customer support requesting they release new sets of rubber bands in different colors - the more emails they get the more likely they'll actually do something about it.

If the above are not acceptable options here is what I'd do:

Assemble the set that requires the rubber bands as much as you can. Use any bands you have at home to finish it.
Determine what's the acceptable difference in size, strength, stretchability and color.
Repeat the same process for all other sets you own that are missing bands.
Shop online for bands that are the closest to your requirements. Amazon, EBay, local equivalents. Maybe you can find a local manufacturer or distributor - don't hesitate to contact them.


How to make a Lego Mindstorms ev3 self driving car?

I don't have a Lego EV3, but I have created a self-driving car with my NXT brick. I found the instructions from nxtprograms.com, but they are for the NXT. (I'm sure that you can adapt them for the EV3 though). The program is also for the NXT, but nxtprograms provides enough comment blocks that I think you should easily be able to build your own program with the EV3 software.

Here are the instructions:
http://nxtprograms.com/NXT2/explorer/index.html


Port problem? Mindstorms EV3 brick doesn't detect sensor blocks

Welcome Violetta. The EV3 Brick has a total of 8 ports - 4 output ports on one side labeled A-D, used for driving motors, and 4 input ports on the other side of the brick labeled 1-4, used for getting information from sensors.

(Image sourced from this page)

Make sure you have plugged your sensors into the correct port, as plugging them into ports A-D will not allow the Brick to detect them.


Variable stick lengths and angles at nodes of building bricks


Compare part lists between Stud.io models?

Since there doesn't seem to be a tool, I've written my own one. In case anyone else want to use it, check it out here: https://github.com/ChrZae/bricklink-xml-diff

Take care tho, it can only really process the XML generated by Stud.io, the XML-format itself has more fields which I didn't care about (also no guarantees it will always work correctly).


What does coming soon mean on the LEGO store website?

"Coming Soon on 1 August 2020" generally means the time when "Add to basket" button becomes available (usually at midnight) so you can actually buy the set. This means you cannot really pre-order it in advance, unless there is some sort of VIP promotion (this is announced in advance), which works for some releases and allow sets to be purchased a day, week or two in advance.
If set is in high demand on release day it can quickly can be marked as "on back-order". That is your order is accepted, but shipping is delayed.


Linear Actuator of the boom of 42006 jams

First off, you should check the instructions to see if you made a mistake before going into some long repair method. Even if you find no mistake, what I would do is disassemble the entire crane assembly and then reassemble it; this would fix problems you may not have noticed. Another thing you could do is remove the actuator and fully extend and retract it a couple of times. If you feel any extra friction while doing this, than the actuator might need lubrication.


Please help identify a set with bag of tan, white, grey, and light-blue 1x1 and 1x2 bricks?

Recently, I bought a used 10214 London Tower Bridge. It came with all parts in one single bag. However, looking at the brick types and colors on the picture I would guess it is from 10214.


How best to plan and design a custom LEGO creation?

This is going to be different for everyone, but there are several different options.

I personally prefer to get my LEGO bricks out and just start building, this usually doesn't turn out exactly how I want initially, but I will take the bits I like and try again; building multiple versions to find what I like and come up with a finished item.  For larger builds, I will break it down into specific areas or elements to focus on and then work to integrate the sections when I am happy with each.

A very useful set of tools are the various computer Lego CAD systems, I prefer LDraw, the official Lego tool is the Lego Digital Designer, and there are others.

I have used these to start from scratch to generate a finished design, to generate a rough idea before moving onto the bricks, or to organize existing elements together into a larger build.

Depending on your experience they can be very useful tools not just for planning, but to generate build directions, parts lists, or high quality renders of you creation.  They will come with a large number of Lego pieces and colors allowing you to experiment beyond the Lego you have.  They are a little cumbersome for certain advanced SNOT techniques but can generally do most things Lego would.


How many motors can be controlled using the Powered Up system?

With current hardware, the answer is 10. From the trains FAQ:

  You can run up to 10 trains at the same time from one remote control. There are 5 channels on the remote control (you can tell them apart by their different colors), and with each channel you can control 2 Smarthubs in separate trains with motors plugged in – as long as on one train the motor is in port A of the Smarthub, and on the other train, port B.

Each Smarthub provides two ports:

There are 5 channels available on current remotes, so you can pair up to 5 remotes with Smarthubs and control 5×2=10 outputs at the same time.


Why did LEGO create different canister for the Visorak?

I heard a similar question about old cars and how one owner had a hood made of steel and another . . . same make, same model, same year . . . had an aluminum hood. The answer as to why was simple . . . it's the metal the manufacturer had at the time. My guess is once the molding machines are loaded with a color they keep using it until it runs out. Some of the colors were versatile and looked good on multiple sets so they could make more of those before switching colors.


Can I share/download a wishlist on Bricklink?

There is no built-in way to download the Bricklink wanted lists. However, there is a userscript that should work for this.

DISCLAIMER:  Use at your own risk. YMMV.

http://userscripts-mirror.org/scripts/show/167618

Firefox with Greasemonkey is the way I use other user scripts, but I wasn't able to get this working with Firefox.  I was able to get it working with Chrome and Tampermonkey.

You'll want to make sure you read the description in the link above, and pay attention to the tips they recommend like increasing the number of items per page so you capture everything.


Did any sets have lots of 1x2 smooth tiles with gauges on them?

No. :)

I checked several "gauges pattern" tiles. There is no set with more than 3 of them.


At last, I have your answer. The figure is from a "Giant Pre-School Loc Bloc" set, likely the "Playground" one shown in the picture.

Nearly a month later, while doing unrelated research, I found "Giant Brix Blox", a second possible source of these types of figures;

It makes since given that sources claim Loc Blocs & Brix Blox were both imported from the Japanese company Kawada.


Ultrasonic problems with the red and blue balls?

The ultrasonic cannot detect the color of objects. It's just to detect the distance between the sensor and an object in it's line of sight.

To find objects in the surrounding area of your robot you have to look all around. This is simply done by rotating your robot or your sensor. When you measure a distance in a certain range (best results between aprox. 10-50cm) you can stop rotating and you have your direction. Then you start to move and check for better results every 10cm or something like that again if you are still facing the right way.

Stoping exactly in contact won't be possible unless you can say I am Xcm away and now can move exactly Xcm in this direction since the ultrasonic sensor cannot measure distances below a certain level (around 5-10cm depending on the size/shape/material of your object).


How do I know if this wooden LEGO duck is real?

Every Lego wooden duck I have seen, whether in person or on the internet, is sitting on a platform with the wheels attached to the platform. This is the original version:

Here is a later version:

Are there any markings on the toy itself that lead you to believe it is a Lego product?


No, EV3 MyBlocks cannot be recursive. If a MyBlock contains a copy of itself, then the following error will be produced upon compiling:

For some reason, LEGO's programming software has become progressively less immediate about notifying you that this cannot be done. In EV3-G, it waits until compile to let you know that you can't do this. In NXT-G (the software for programming the NXT), trying to put a MyBlock in itself produces an error upon placing it. And in the Robotics Invention System 2.0 (the software for programming the RCX), it simply won't let go of the MyBlock you're dragging if you try and place it into itself.

If you want a programming language for the EV3 that supports recursion, I'd like to offer LeJOS EV3 (Java-based, free) and ROBOTC (C-based, costs money) as alternatives. They're both EV3-compatible, and support recursion.


Help with identifying Lego set (partial red and yellow bike)

This is from set # 9441: Kai's Blade Cycle

Keypart;
85970 - Slope, Curved 10 x 1, in Red


What are the characteristics of "Miniland" scale?

Mini style {used in LEGO sets and by collectors, not Miniland}

Mini scale/style is typically much smaller than normal LEGO. In Mini scale/style, figures are formed with 2-3 blocks.

Mini scale/style {if I remember correctly} didn't gain popularity until recently. It's so far been popularly used in the LEGO Architecture sets, and in a few others of common landmarks.

It's also common to see three-to-five-dollar packages that contain buildable models {sold in the LEGO stores} in the Mini scale/style.

Examples of Mini sets include:

4837 Mini Trains
5761 Mini Digger
5864 Mini Helicopter

Miniland style {used by Legoland amusement parks and a few LEGO sets}

I believe that the LEGO amusement parks use something close to miniland scale. It is, however, much different than normal Mini style/scale. One notable fact is that the people have larger heads. I know this is true for the one in Billund, but I'm not sure about the one in California.

Here and here are the pages of Minilands Billund and California, respectively. The Billund miniland doesn't have its' own page, but it's on the interactive map at the link provided.

A Miniland Flickr group is here if you want to see what Miniland style/scale is.

EDIT! As Zhaph-Ben Duguid pointed out, the Legoland amusement parks are called Miniland, but do not use the Mini scale/style. They use a strange hybrid between DUPLO and LEGO Mini scale/style. It is actually not the more common Mini style/scale used in sets. I've updated this answer to reflect that.


There is a great video on YouTube that shows how to repair this.

https://www.youtube.com/watch?v=eCZNc7tPop0

Basically, there are some surface mount capacitors on the PCB board for the screen/buttons that need a little bit of soldering to make sure they are properly electrically connected.

I have performed this repair myself with success.


How were these building instructions from the 1970s produced?

They would have been hand drawn.
Technical illustration used to be a highly skilled job, similar but slightly different to design draughtsmanship.  I can still recall the latter being used about 20 years ago in engineering.  There were tricks to remove some of the repetition (drawings were done on translucent drafting film and could be duplicated optically, and templates and stencils were widely used).  Translucent film also means it was possible to work on an isometric grid behind the drawing.
2D CAD software, while it dates back to the 1950s, only became accessible, though still very expensive, around the time these 3D drawings were produced.  3D CAD/modelling with rendering is a 1990s invention, and now any fool can use it (e.g. me), and it can be made cheap and user-friendly enough to give away (e.g. Lego Digital Designer).  Rendering using something like POV-ray (which can still be used with LDraw) could take days for a single image on a fast PC in the 90s (though you wouldn't need to render like that for these illustrations).
Also, while it's hard to tell with the JPG artefacts and anti-aliasing, if you look closely at say the wheels in panel 8, they're not quite a perfect match; they would be if rendered from the same model.
Here's a picture of what's available at the click of a mouse these days (2020):

I used this 3rd party model of a 2x4 brick and a range of view options in Autodesk Inventor (3D modelling software).  The top right clearly imitates the old manuals, and the style is called "Technical Illustration".  Lego tend to use fairly heavy shading on studs, demonstrating that clarity and style are closely related. Newer instructions use thinner black edges (with better quality printing). The bottom right is suitable for box art but doesn't clearly show the joins between bricks - at a glance the bottom could be a 2x8.  This took less than a minute to render on 1 core of my desktop; 20 years ago it would have taken hours.


6 x 14 plate with 2x12 plate molded on top and metal contacts on the bottom identification

Part# BB0054 - Electric, Train 4.5V Battery Car Roof.

(But Light Gray in color.)


The LXFML file is an XML document, and there's an XSD document that you can use to validate any LXFML file, along with a textual description of the tags on the LUGNet forums supplied by the LDD Team a few years ago:

  LXF files - info and XML schema

The key parts of the LXFML you're going to be interested in start with the <Scene> element, which contains one or more <model> elements, which in turn contains one or more <group> elements, which are made up of <part> elements.

The tricky part is getting from a <part> element to an actual model:

<Part refID="0" name="m3680_turn_plate_2x2__lower_part_0" designID="3680"
      materialID="1" assemblyID="74340" assemblyRefID="0"
      angle="0" ax="0" ay="1" az="0" tx="0" ty="0" tz="0" />

As you can see, the Design ID corresponds to a LEGO element [part:3680] so you'll need some way to get from those to a suitable model - I recommend taking a look at either:

BricksViewer - A Java app for viewing .lxf scene files - also has a brief discussion of the .lxf and .lxfml formats.
LDXNA - An XNA library for importing LDraw models - it does include an .lxfml document in one of its examples, but I don't recall it using it - however it does show you how to convert the LDraw parts library into a usable format.


Mecha Rail Launchpad Building techniques?

Based on your drawing and description, the closest analogy to your idea would be a railway turntable, where the mech bays would be akin to the roundhouse and the "exit" on your diagram represents the connecting railway to the turntable switching yard.

LEGO models of such structures can be found and analysed for their various building techniques to see which ideas would suit your expectations and situation.

Rails: yes or no? Obviously these models are designed with LEGO railway pieces in mind which might or might not be suitable for your MOC. Using the existing railway system offers a few advantages, like a complete ecosystem for straight and curved rails, wheels, carriages, switching points, couplings, etc. and might even look suitably industrial and heavy-duty. On the other hand their usage seriously limits the possible geometries (wheelbase length, minimal height of the carrier trolley, etc.), defines the look of the model and might provide challenges with the connection of the turntable and the static rails. Another option would be to use carrier trolleys with rubber wheels on a tiled surface to get around some of the above restrictions.

Implementation of the turntable itself The basic component is a circle-shaped, pit-like structure with a radius big enough to fit a carrier upon the rotating bridge above it and with enough depth to house the end supports, the central pivot column and the mechanism used to motorize it if needed. The central pivot and the end supports must be strong enough to hold the combined weight of a carrier and a mech on any point along the tracks on the turntable, which would mean either really sturdy supports or a carrier long enough to distribute its weight among multiple supports and the ground around the structure.

SIDE CUTAWAY VIEW OF THE PROPOSED STRUCTURE
                                        MAGNIFIED VIEW OF
 mmmmmm      mmmmmmmmmmmmmmmmmm       THE DRIVING MECHANISM
 oo==oo      o==o   o==o   o==o    /   ----------  -------
 ------ ----------------- ------  /         d|b3   MMMMM##
 ######  T      A      T*~MM#### <           *~~~~~MMMMM##
 ######  !      H      !  ######  \                MMMMM##
 ########^#############^########   \               #######

Legend:
# "Solid" ground
- Rail for the mecha carrier trolley
o Wheels of the carrier
= Structure of the carrier
m Feet of the mecha, or upper structure connecting multiple carriers
T End support structures
! Support structures with tiny wheels on their bottom parts
^ Suitable rolling surface for the end support wheels (rails or tiled surface)
A Central axis pillar
H Central pillar structure
M Motor for driving the ring
3 The inner gear rack of a Bucket Wheel Excavator ring
d|b A gear with a vertical axis, meshing with the gear rack ("3")
* A mechanism for turning a horizontally rotating axle into a vertically rotating one
  (like two bevel gears or a gear and a worm gear)
~ Horizontal axle

End supports and their wheels The end supports must travel along the bottom edge of the pit, supporting a great portion of the carrier and the mech, while losing not too much energy to friction. This calls for wheels, but even here we have many options:

You can certainly use generic railroad tracks if the dimensions permit it (the radius of the pit is just a few studs larger than the outer curve radius of the LEGO rail pieces)
For smaller dimensions the narrow gauge rail tracks might be used
The newer roller coaster pieces could be an alternative if a suitable wheel setup can be constructed either from scratch, or built around the existing rollercoaster cars
At least one example I have seen uses monorail tracks, if you have those, feel free to use them this way
Tiles and road wheels are certainly the most flexible option regarding the possible diameters but they tend to have a lot of resistance compared to non-flexible wheels on rails
Some Technic sets, like the 42054 Claas Xerion tractor, the 42082 Offroad Crane or the 42055 Bucket Wheel Excavator for example feature such turntable solutions that can be used as inspiration

Motorization You haven't mentioned if you'd like to use a motor to drive the turntable, but if yes, then you have a few options here as well:

Train engine on rails as the "feet" of the end support(s)
Motor housed in the end support(s) propelling against the wall of the pit
Motor housed in the central column
Motor housed in the wall of the pit propelling the turntable by its edge

The first two options require either a battery and control system built into the moving parts of the turntable itself, or wires that can feed the built-in motors from a static battery - but this option must be used with limiters or the wires might get tangled or snap. The third needs extensive gearing down to be able to handle the load and all losses without overstraining the motor. The last option avoids these problems but requires the turntable to be a complete ring with an interface suitable for propulsion (either a smooth circle that can be driven via friction from multiple rubber wheels, or a circular gear rack - The specialised parts from the Bucket Wheel Excavator or the 4481 Hailfire Droid wheels would be my first idea).

If you have any more questions, either in general or regarding a specific problem, feel free to ask - I'd love to see your project come to fruition :)


This is the rear part of 70009-1: Worriz's Combat Lair:


It's a bb42 "Electric, Light & Sound Siren 4 x 2 x 4 Jack Stone"

http://www.bricklink.com/catalogItemIn.asp?P=bb42&in=S

and in that colour it came in the Police HQ set 4611
http://brickset.com/sets/4611-1


Generally speaking, the 4.5V motors have higher torque than the higher voltage variants, but run at a much lower RPM.  I have never personally tested this particular motor so I can't say specifically.

Utility is in the eyes of the beholder.  For some people, this would be the exact motor they need.  For some, it would be useless.  It's hard to say if it would be useful/less without a specific application.

You can always order the LEGO branded cable/connectors from Bricklink or similar sites.  However, it's quite easy to make your own cabling for the 4.5V motors if you are so inclined.


How can I invert the direction of blocks in a structure?

It depends on how close they need to be.

The following solution works, if you're happy to have things sticking out around the join:

"Brick 1x2 M. 2 Holes Ø 4,87", [part:32000:7]; There's also a 1x1 brick with a hole, [part:6541:7].

Which could be used as:

For tighter coupling, the Minifig Wrench [part:6246d:0] can also fit over a stud, and is deeper than one stud, allowing two bricks to be inserted:

Respect goes to Erik Amzallag for this one.

I guess it comes down to how you want to hide the join - you could use tiles on the studs that stick out, which wouldn't be possible with the wrench method.


How to locate objects, and move towards them, without pre-programming the path

If the ultrasonic cannot echo-locate the objects because they're too small, even with the sensor suspended very close to the floor, I suggest using a very sensitive feeler out front. It can be sticking forward like a jousting lance, and your robot can swivel back & forth while traveling to scan.

The trick to making it very sensitive is to:
(1) make it pivot at its base on the front of the robot with a smooth pin,
(2) make it long and lightweight (use long axles),
(3) mount two opposed touch sensors as close to the pivot point as possible, and
(4) pre-load the touch sensors such that minimal travel is necessary to trigger each one.

The same techniques can be applied with a large diameter roller out front (like a steam roller) to detect any bumps on the floor (if the objects are kind of flat).


Why does LEGO now use studless technic designs?

The studless have SEVERAL advantages over the studded design especially when you want to include moving parts. Just the clearances between connections is important. Sariel sums it up in his book well. He says there are advantages to both systems (stud-full, for example, are more rigid) but the fact that the stud-less look more realistic and, of course, the clearances, make a huge difference. I think the change was NECESSARY to build more realistic models (realistic looking, arguably, but the new models are very mechanically clever in ways that would be impossible with the stud-full parts).

According to Jamie Berard, these advantages were a major part of the gradual migration, as was a flaw in the studded beam design-- the holes in studded technic bricks are placed slightly incorrectly according to the LEGO "System". That means for technic model designers, working with studded beams (and staying "In System") provides many difficult challenges.


Looking for empty LEGO boxes for 6389 Fire Control Center and 6669 Diesel Daredevil

You can buy boxes for most sets from Bricklink.com. For example, there are world-wide three sellers of the box for set 6389. Unfortunately, getting a box for such an old set will set you back $40-$50, excluding (international) shipping.

For set 6669 there are currently also 3 sellers, with prices ranging from $5 for a severely damaged box to $30 for boxes in good condition, all prices excl. shipping.

Of course there are other places to look, such as EBay or local classified sites like Craigslist in the US, but chances you find one of these boxes there are minimal. Bricklink (or its competitor BrickOwl) are your surest bet.


What are LDUs and how do they relate to LEGO bricks?

LDU stands for LDraw Unit - the basic unit of measurement in LDraw, the open standard for LEGO CAD programs, and map to the "Fine" grid setting in applications such as MLCad.

Common measurements include:

1 brick width/depth = 20 LDU
1 brick height      = 24 LDU
1 plate height      =  8 LDU
1 stud diameter     = 12 LDU
1 stud height       =  4 LDU

A 1x1 Brick as 3 Plates in LDUs (via LDraw)

The typical LU (LEGO Unit) measurements are coarser at:

Brick height = 6
Plate height = 2
Stud pitch   = 5

Based on the physical dimensions of a LEGO brick, this means that 1LDU == 0.4mm, based on a stud height (1LU) of 1.6mm.


Well the thing with LEGO, (Technic, Classic, Mindstorms or whichever category you talk about) is that it is customizable. You might not get instructions to combine Power Functions with this kit but you can figure out a way or look at other people who have done it. No, you cannot straightaway attach Power Functions with the 42048 set. There are sets (at higher prices) which have been designed to contain the PF elements. So no the power functions symbol is not there on the 42048 box.

However I encourage you to go ahead and try to attach the 8293 PF elements to any Technic set you have since you probably can fit the parts into most sets.


I think LabVIEW only works with 3 motors. You could use EV3-G instead.


What's the deal with the single-type-of-piece bags on Amazon?

I think it's really hard to tell for sure without actually making a couple of orders and seeing what arrives. What I can say is that it appears that they are selling at a HUGE markup over similar parts available on Bricklink. (A quick check shows an average markup of 600% over BL on several lots)
I would guess that either the first, third, or some combination of those two guesses is likely to be the case here. Since secondary markets like BrickLink and BrickOwl are somewhat niche sites maybe the seller(s) are taking advantage of people unaware of them and selling at a very good profit to a larger market. Additionally since Ali Baba, Ebay, and Amazon tend to have a large number of counterfeit sets available these sellers may be able to get away with selling all or a mixture of counterfeit parts to increase their margins.
As for your second guess, there are programs that The LEGO Group makes available to organizations of various sorts to acquire large numbers of pieces at fairly reasonable prices however they do tend to monitor the secondary market fairly closely for evidence the parts from those programs are being resold so, while certainly still possible, it is less likely the parts are being sourced that way.
Again though, it is nearly impossible to tell simply from the advertised lots without actually making a purchase to verify what you would get.


How to build a flywheel crankshaft piston pattern with technic?

Here's one simple way to accomplish this using just basic parts:

This isn't quite a pure Technic example, but that construction is almost exactly what was used on the steam cylinders on Emerald Night:

Depending on exactly what you are trying to do, there are also some specialized parts that make building decorative pistons simple. For example, here's the V8 from the 8880 Super Car:

There's also the much earlier piston design on 853:


Please help identify this set with red, black, and lime colors?

Based on the printed Atlantis part, this looks like Neptune Carrier (8075-1).


That's Flag 5 x 6 Hexagonal (x1435). The lack of any numbers explains why "x1435" was used to catalog the piece, back in time when official part numbers were unavailable. Dark Blue coloured element was available in 6 sets.


If you're interested in comparing motors regarding to torque and what they can deliver, I would recommend  reading Philo's excellent motor comparison page which has a lot of detailed information, very much useful for tinkerers.

Of course not all of these motors are readily available nowadays and depending on your project some may be less suitable; but there's a good chance PF motors are what you're after.

While 8293 which you mentionned is a simple way to get one motor, keep in mind you're also getting a lot of extra stuff which may or may not be useful to you. In particular, battery boxes tend to get superfluous very fast (YMMV on this). So buying motors only might be a cheaper route; they are available per piece on LEGO's online shop - 8883 is the same as the set 8293; 88003 is a more Technic-oriented version and 8882 is the "XL" motor: slower, but with a lot of torque. (Again, read Philo's comparison). On the other hand, if you do want a battery box, it might be more interesting to buy a full motorized LEGO set, in which case you also get tons of additional elements, and the added thrill of building an official set. Beware that some motorized sets also come with IR remote & receiver, which may or may not interest you.

Note that the Power Functions system itself is going to be phased out by LEGO in favor of the newer Powered Up; but so far it's not quite clear if and how you can control those without a remote or app, as there's no "dumb" battery box so far - only hubs with more or less smartness.

And of course, since you're a programmer, you may want to have a look at programmable solutions, either EV3 or the upcoming Spike.


Bazooka blast ev3 Mindstorms using Python

ev3dev works pretty well for that purpose, and all you need is a microSD card.

You'll need to use the Motor class. It work with both large and medium motors, and either can be use to shoot balls, so this part will be at your preference.


How many styles of element separators has LEGO produced?

Bricklink lists two:

OLD: http://www.bricklink.com/catalogItem.asp?P=6007

NEW: http://www.bricklink.com/catalogItem.asp?P=96874

There is one other 'separator', but it doesn't look like it's very good for bricks: http://www.bricklink.com/catalogItem.asp?P=x1220

ETA: The Clickits Separator! http://www.bricklink.com/catalogItem.asp?P=clikits021


What is a color sensor and where do you get it?

The Original Mindstorms NXT only came with the NXT Light Sensor. The NXT Light Sensor cannot detect colors, so this is most likely what you have. You can currently purchase the NXT Color Sensor from Bricklink.com for under $30.


What different types of LEGO train tracks exist?

The main LEGO train systems are all roughly compatible. They all use a 6 stud gauge, so with a bit of fiddling, you can use all of the systems together. If you want to be most compatible with the current track offerings, you're better off with 9V and RC/PF track. This question discusses the specific compatibility issues in more detail.

There are several other train systems that have been used that are not compatible (DUPLO trains, 4 guage rails, etc), but I'll just cover the common 6 gauge systems here.

The different types of train track can be divided into a few main eras.

Blue Era (1966 - 1980)

A track section consisted of 2 rails connected by regular 2x8 plates. The rails themselves were blue.

Trains could be either pushed by hand along the track, powered via 3 batteries (4.5V system), or powered via a third conducting rail added to the center of the track (12V system). Here are what the conducting rails for the 12V system look like:

Some people still prefer the 12V system because it included more remote controlled components than the later 9V or RC/PF systems. With later systems, the only thing that is easily remote controlled is the train itself, whereas the 12V system included remote controlled points, light, and decouplers.

Each era included straight track, curved track, switches, and cross track.

Gray Era (1980 - 1991)

These rails are generally the same as the blue rails aside from the new gray color.

The sleepers were moved closer together (3 per section rather than 2), and they were changed to a specialized part to improve the strength of the connection. Here's what the sleepers look like:

The trains of this era were still either powered by 4.5V batteries or the 12V conducting rails.

9V Era (1991 - 2006)

The 9V era completely changed the track components, and did away with the old 4.5V and 12V voltages. Rails sections were a single piece, and they were all conducting.

The 9v system included straight, curved, switch, and cross track.

RC / Power Functions Era (2007-)

In 2006, LEGO switched back to non-conducting rails with roughly the same mold as the 9V track. Trains are now all battery-powered under either the RC or currently the Power Functions and Powered UP systems.

This era included the first and only crossover switch (7996) :

It also introduced flexible track:

Switches are also available, but a cross track has not yet been released for PF track.


Which LEGO vehicle set do I have here? 6 wheels and orange bricks

Set 4635 - Fun with Vehicles. Specifically the tow truck pictured top center.


Tall red piece with coffee cup, phone and gas picture?

This brick comes from set 6393: Big Rig Truck Stop from 1987.

The official BrickLink name of this brick is 3755pb01 Brick 1 x 3 x 5 with Cup, Phone, and Water Tap Pattern


According to the BrickLink inventory, there should be three extra parts, so 9 seems a bit high.

It could be a mistake from LEGO, but honestly it's more likely that you forgot them yourself. Knowing what the 6 parts are through Bricklink, I suggest you check the model once more to verify where they could go.


Gev already answered the question about availability. LEGO Ideas sets are produced in small quantities. Perhaps this will change in the future as LEGO Ideas is now out of beta testing and was brought in-house by LEGO. The Curiosity is not going to be back unfortunately. I just called LEGO about this a couple of days ago.

As far as the Curiosity inventory, BrickLink has the full parts-list here: http://www.bricklink.com/catalogItemInv.asp?S=21104-1. None of the parts are rare or difficult to find. You can use the parts-list linked above, add them to your wanted list on BrickLink, then quiry your wanted list by shop. This will show you which stores have all the parts you need in stock. And you can download the building instructions from LEGO's customer service website here: http://service.lego.com/en-us/buildinginstructions/


Lego mindstorms ev3 spinner factory problem

My Blocks can have input and output parameters.

What you're seeing is an input parameter.

This particular My Block has as input parameter the color the factory bridge needs to drive to.

If you create a My Block from a selection of blocks and there are already data wires going in or out of the selection, input and output parameters are created automatically.

You can also add or edit input or output parameters in the My Block Builder dialog.

Perhaps this tutorial helps:
http://stemrobotics.cs.pdx.edu/sites/default/files/MyBlocks%20%281%29.pdf


Education EV3 Software Site Licence - installation on teachers computers?

You can check out
https://education.lego.com/nl-nl/educationdownloads/productpage/?AccessLink=985ff951-4b98-467d-9f16-687487a43784&ignorereferer=true

I think this is were you can find the student version, quite similar to the teachers version.


What is the maximum voltage for motors from Cybermaster units?

I don't have this set, so I can't provide a fully authoritative answer, but 9V is likely to be safe for these motors. The hub that drives them is definitely 9V, as it connects with the rest of the 9V system and runs on 6 AA batteries:

TLG typically overspecs their motors somewhat, so you could probably also get away with running the motor using 12 volts, but it might harm the life expectancy a bit. If you can pull out the actual motor, you might be able to find a model number to look up for a more authoritative answer.
I'd recommend starting with a lower voltage (perhaps 3V) and working your way up to make sure that the motors are functioning as expected.


Are there any sets without a lot of fluff?

While nearly all sets these days to include a certain number of parts that you may be referring to as "fluff", the Classic line has the highest ratio of more typical bricks and plates that you may be used to and has a number of sets at quite a few price points that may be useful to you and are available both direct from LEGO and from many retailers.
A note of caution over your classification of those "fluff" pieces though: You may find if you progress to more advanced building techniques that many of those pieces you currently disdain are absolutely indispensable to accomplish some very interesting effects that are simply not possible with standard bricks and plates. Don't discount the utility of a part simply because you may not be familiar with their usefulness or that they may not be immediately related to your current project. A fairly common term in the community is NPU which stands for New (or sometimes Novel) Parts Usage and stems from people being very creative with parts that might not immediately seem to have any other purpose than their basic form might suggest, and has led to very interesting and quite stunning results.


That's Torso LotR Shirt with Ornate Silver Fabric and Gold Clasps Pattern (Saruman) / White Arms / Light Nougat Hands


Factories that could make off-patent bricks?

I suggest calling Lego customer service (1-800-835-4386) to ask them about a bulk order. Professional "brick artists" like Nathan Sawaya buy their brick directly from Lego. The bulk prices are decent as well. For example, through the LUGbulk program, we got 2x4 bricks for about 9.6 cents each (these sell for $0.30/ea on the Pick-a-brick website).

Also, here is a long list of manufacturers who can do custom ABS injection molding: http://www.thomasnet.com/nsearch.html?which=prod&cov=NA&what=Custom+Injection+Molded+Plastics&heading=95958385&k=abs&x=16&y=9&navsec=modify


Every time Robot is launched (without changing the code) it is not following the exact path

This is actually a fairly typical problem, with several possible causes.

The motors do not directly drive the axle, there is a gear train hiding inside the plastic casing.  That gear train can be deflected without turning the motor.

The software controlling the motor maintains a last known position so that several move blocks can be run in sequence and the over/under at the transition between blocks is taken into account.  This is typically a problem when the robot is picked up during an aborted run, and the program is rerun.  The robot acts like it remembers the previous run and twitches to the left or right when it is restarted.  There is a motor reset block to handle this problem.

Dirt/dust on the wheels can also cause issues, as can wheels not firmly positioned on the hubs.  This year we spent a whole session trying to get the robot to go straight and ended up trading wheel/hubs until we found a pair that worked fairly well.

Some wheel/hub combinations slip.  We spent a long time thinking some old yellow hub + shiny black wheels would work.  What a mistake.  The wheels didn't slip at first.  After a couple runs that smacked into the wall and they loosened and nothing, not rubber bands, not different hubs, not ...

The big message isn't to find a combination that goes straight.  Expect it to wander.


How quickly do new molds reach PAB on the Lego website?

I suspect that is unanswerable except in very vague terms like "some time after the new molds get put into production" and "it will be a LONG time before the old ones go away completely".


Further to Alex's answer, from that source I found eleven colours that only lasted a year:

Fabuland Orange 1983
Very Light Orange 2000
Clikits Lavender 2005
Chrome Black 2009
Chrome Green 1999
Satin White 2020
Satin Trans-Light Blue 2020
Satin Trans-Dark Pink 2020
Glitter Trns-Orange 2020
Speckle Black-Copper 2006
Speckle DBGray-Silver 2006

Of course the four 2020 colours may continue next year!
Fabuland Orange was only used for one item in one set for one year, so could be considered the rarest colour.  The set was "Peter Panda Takes a Bath", and the part was Peter Panda's tub, a part barrel affair.


How can I get replacement Mindstorms NXT components?

I don't think there's a way to buy all non-electronics parts other than buying them all one-by-one, which doesn't seem to be a solution for you. Note that contacting the LEGO customer service may be an option, but I'm not sure how far they'll be willing to help (and as you said it probably won't be cheap).

The only other idea I can suggest is to work the opposite way: try to sell the electronic parts you still have; that way you can just buy a complete kit again.

I realize it's not really easy either, but there could be some people who have already so much regular LEGO parts that only electronics interest them, and they don't want to pay too much money by buying these separately. Or maybe someone has the kit and lost some of the electronic parts.

Of course, don't underestimate the use of having extra electronic parts - your robot can get much more interesting; and in particular, learning to program two different NXT bricks so that they communicate properly to achieve a common goal can be very educational. Also, considering a full kit is usually cheaper than buying all elements in there separately, I believe buying it again is a more interesting thing to do - although I understand the price can be a serious issue, especially if you want to buy the newer EV3 version.

There may be another thing you can try: as you probably know, LEGO has educational programs based on robotics kits, and it could be that a school/college in your area is using these. Try to contact them, and see if they would be willing to either sell you unused parts (maybe because they are upgrading to EV3) or to buy your electronic parts (if they lost or broke some). I'm not sure if you can contact LEGO Education to try to get a list of schools using mindstorms in your area, but it can't hurt to try.


What version of Lego Digital Designer has all the parts that LEGO ever added?

I believe that the last version that had a complete set of elements was 4.3.11, however that has dependencies on Adobe Flash, so will likely not work on most modern systems that have now removed Flash.
The last release, 4.3.12 has a known issue with missing parts. However you can use the parts library (Assets.lif) from 4.3.11 with 4.3.12 - this can be extracted from the installer if you open it with an archive explorer (i.e. 7zip or similar).
Bear in mind that:

To see all the parts, you may need to enable "Extended Mode" (View | New themes | extended).
LEGO Digital Designer is no longer actively supported. However The LEGO Group have purchased the team behind Studio, which is actively developed and has new parts regularly added.

Edit to add:
Glad you've managed to get it working in your preferred version. I'm not aware of people adding more elements to the official library files, but I've not really looked for it.
Whilst we can't say exactly what The LEGO Group will do in the future, they did say when they acquired BrickLink that:

The LEGO Group is planning to support and evolve Studio and will review opportunities for both services following the closing of the deal.

They also released a video last December (2020) where they updated on the future of both BrickLink and Studio.

In addition, we're going to upgrade the Studio software every month to improve the user experience and enhance it's performance.

Finally, as a quick test, I was able to find the Fright Knights Witch and Bat Lord heads and torsos fairly quickly in Studio:

Others are likely available.


This is part 2060 - Windscreen 4 x 4 x 3 Canopy in Trans Black (Smoke)

Image from Bricklink
The part in that colour is only available in the Star Wars Slave I


What is the best solution to power up two 5292 buggy motors?

The Lipo, thermal protections kicks in when consuming about 1A, while the buggy motor will consume 1.3 A when loaded but not stalled.
So for two buggy motors, best would be 3 lipo's in parallel but perhaps you can get away with 2.
The V1 receiver, only 850 mA before the protection kicks in, so not enough to power 1 buggy motor, let alone 2.
The V2 receiver, 1.5 A before the protection kicks in, enough to power 1 buggy motor...

What might be a solution is having the V1 receiver control a medium motor or servo which mechanically switches a 8869 control switch which in turn switches the buggys on and off...

As for the old battery box, I think the reason you don't get it to power a V1 receiver is because power functions have two pairs of wires, a control pair and a pair that gives a constant voltage.

M,L and XL motors only use the control pairs of wires.

A servo uses the voltage pair to keep its position and the control pair to determine the position.

A receiver uses the input voltage pair to power itself, ignores the input control pair, forwards the voltage pair to the output voltage pairs and places control voltage on the output control pairs as it's instructed by the remote.

When using PF to 9V conversion cables, I think only the control pairs get connected, never the voltage pairs so the receivers cannot be powered by 9V battery boxes or cables...


In principle, this will work although as D M notes (assuming a non-inverted build), the 1x1 bricks won't attach to the palm top correctly as they aren't long enough - a 1x1 round plate with hole on the bottom will help - either the same colour as the candle or as a part of the holder.
You might find that the candles are too close together for you as they would end up touching:

If you aren't worried about stability, by inverting the the 1x1 round bricks and resting the pin-holders upside down for a more "used" look, however the pin holders aren't secured:

Other options you might consider include using:

The very old 5x5 Propeller with 4 blades, very limited colour set
Plate Round 4x4 with hole
Two 1x3 plates stacked crossways, with 1x1 plates to provide additional support and conformity (as IvanSanchez suggests)
Plate, Modified 3x3 Cross, only available in a limited colour set, but available in at least black, brown and reddish brown (as Matthew Jensen suggests)
Axle Connector Hub with 4 bars and four Bar Holder with clip to hold inverted pin holders

The Haunted House set uses a Pearl Gold Technic Knob Cog in its chandelier, shown with the Candle element:


Will the LEGO MINDSTORMS EV3 software run on macOS 10.15 Catalina

I just updated to Catalina Beta 10.15 and as expected, the software no longer starts.

The same happens with both the Home and the Education version.

Source: https://education.lego.com/en-us/support/mindstorms-ev3/software-launch-issues

Alternatives

If you are an existing EV3 Desktop software user and depend on being able
to use existing programs or curriculum, it is highly recommended to either not upgrade macOS or to install a macOS or Windows virtual machine, such as Virtual Box, on your Mac to run the old version of the LEGO EV3 desktop software. There is no direct replacement for this software and no way to automatically convert programs to any of the new software alternatives.
At the end of November 2019, LEGO released a macOS version (English only) of their new programming software based on the Scratch programming language. This software is good for basic programming, but lacks advanced features like data logging, file access, brick-to-brick Bluetooth messaging, and 3rd party sensor support. Home. Education.
For users needing advanced features, the LEGO Education MicroPython for EV3 is the recommended solution. Download.

Info below is kept for historic record.

Updated LEGO announcement (September 2019)

LEGO has made an announcement about a replacement software.

  The current version of the EV3 Lab software is not compatible with the upcoming release of Apple’s operating system for Mac computers, called ‘Catalina’. We have therefore decided to replace the current EV3 Lab software and EV3 Programming App with a completely new app, called LEGO® MINDSTORMS® Education EV3 Classroom. Featuring a coding language based on Scratch, EV3 Classroom will initially launch for macOS in November 2019 and in spring 2020 for iOS, Windows 10, Android and Chrome. EV3 Classroom will offer a consistent experience, features, and content across all devices. The first release of EV3 Classroom will be in US English, followed by the other 15 EV3 languages in spring 2020.

  To continue to enjoy an uninterrupted EV3 experience, we recommend that you upgrade to the new EV3 Classroom app before updating to the new OS version. For further questions and support, you can to reach out to Technical Consumer Service at https://education.LEGO.com/en-us/support.

Original LEGO Education announcement (June 2019)

The LEGO Education website says:

  Attention Mac Users: This Software will not work with future versions of MacOS. We are aware of this and we are looking into a solution.


What is the three-position lever in the Bugatti Chiron supposed to do?

You have two of three right:

One position is the Drive, where the wheels are connected to the engine via the gearbox
The middle is the Neutral, where there is no connection between the wheels and the engine
And the third should be the Reverse, where the wheels are connected to the engine but with passing through a reverser instead of the gearbox.

This is the relevant part, the lever in question hooks into the gray transmission driving ring in the middle and connects the central axle either to the red or the blue gear:

If the reverse is indeed missing, you might have made an error during assembly. Finding and correcting such an error will most probably involve disassembling the whole bodywork and some of the undercarriage, then rebuilding everything back again. For this reason it is generally a sound advice to double-check the parts added in each step and periodically check the already built subcomponents to see if they work as expected.


I have 2 Banbao set from before the lawsuit with Lego (minifig style minifigs) and they are more and less compatible with lego, the pitch between the studs is the same. But there is some remark I noticed within comparing both brands for a few minutes.

Studs are higher, a Lego plate on a Banbao brick will leave a small gap between both bricks
Plates are thicker. Lego ~3.2 mm and Banbao 3.6 mm. Bricks -> 11.4mm instead of ~9.6mm
Fit between Banbao bricks can be loose.

I have a small pull-back car that contains jumper plates that are placed vertical, parts mounted to them will fall off.
Bushes just slide over cross axles as there is no friction between both parts
Hinges are loose.
Usage of large parts, like 24x10 molded piece as a base for a vehicle.

I don't know if the quality of the bricks is better nowadays or they changed the dimension of the bricks. I would say just go to the store and by the cheapest set you can find and look for yourself.


Is a N2 or CO2 paintball tank a viable power source for a LEGO pneumatic Engine?

Apprently, it is possible to generate up to 37psi with LEGO pneumatics parts only.

LEGO penumatics can withstand more, however. Engines similar to the one you want to build can work with a recommended pressure intake of 90psi; a maximal (but not recommended) of 120psi is mentionned.

So I think it all boils down to the pressure your N2 or CO2 tanks can generate, under 100psi should be OK. If not, I suppose there could be some way to get it down to that level.

As for using N2 or CO2 instead of air, I don't think there is much reason for concern, since both are faily harmless and present in air anyway.


Identifying some hair, a green "gem", and white minifigures accessory

Piece 1 is Mega Bloks. Here's is a picture of a head (twice) that goes with it, and some yellow hair as well.


Are there more instructions for LEGO Architecture Studio?

I don't think so.  I've found a few places that show nothing but the original book for it in terms of official LEGO content:

http://lego.brickinstructions.com/lego_instructions/set/21050/Architectuer_Studio
https://www.repubrick.com/index.php?option=com_virtuemart&view=productdetails&virtuemart_product_id=451&virtuemart_category_id=38&lang=en
https://www.reddit.com/r/architecture/comments/1k108y/the_lego_architecture_studio_manual_via_legos/

Tom Alphin's book

While it isn't entirely instructions it does include lots of instructions: Tom Alphin's book The Lego Architect.  It has been a while since I flipped through it so I just gave it another skim.  I'd say that a third to a half of the pages are dedicated to detailed instructions.  The rest of it is lovely inspiration so it isn't like filler.

Brick Architect blog

Tom Alphin also has created a blog that has lots of LEGO architecture designs in it: http://brickarchitect.com/ but I didn't see any instructions there.  It is still probably worth checking out for inspiration.


What is the special LEGO Movie 1x1 element shown in the Channel 4 documentary 'Inside LEGO at Christmas'?

The Piece of Resistance

can be found in 11 sets

bricklink link


EV3Dev Gyro sensor doesn't output values beneath 0

I'm assuming you are using ev3dev-lang-java. It looks like this bug was fixed in v2.6.0. Source.
Make sure you are using the latest version. With your EV3 connected to the Internet, run sudo apt udpate && sudo apt upgrade.


Evolution of the LEGO part catalog over time

You might be able to get the information that you are after from the Rebrickable database dumps. This includes set inventories for many sets, along with the year that the sets were released. Here's the full schema diagram:

A query something like this should provide a count of the number of sets every element has appeared in by year:

SELECT year,
       Sum(1),
       colors.name,
       parts.name,
       parts.part_num,
       colors.id
FROM   sets
       JOIN inventories
         ON inventories.set_num = sets.set_num
            AND inventories.version = 1
       LEFT JOIN inventory_parts
              ON inventory_parts.inventory_id = inventories.id
       JOIN parts
         ON parts.part_num = inventory_parts.part_num
       JOIN colors
         ON colors.id = inventory_parts.color_id
GROUP  BY year,
          colors.name,
          parts.name,
          parts.part_num,
          colors.id
ORDER  BY year DESC,
          colors.name ASC

Here's that dataset:

https://gist.github.com/jncraton/b0641ce5f8bc28e10e761a5ce1bafd51

Note that this query includes part variations (mold updates, prints, etc) as unique elements, so you may need to filter it down quite a bit for your use case. If you'd like to run your own queries directly against the full Rebrickable dataset, I maintain some scripts that make this fairly easy to do.


What is the biggest LEGO-compatible one piece wheel?


The best way to figure out what colors a set of parts have in common is to use BrickLink’s Stud.io digital design software. I am unable to show screenshots at the moment, but here are the steps:

Open Stud.io
Place the parts in question on your virtual building workspace (doesnt matter in which color)
Select all the parts together, either by:

using the mouse to draw a selection square around the parts
using the mouse and the CTRL key to select parts one by one
using the parts list on the right side of the screen (the Step list) and with CTRL pressed selecting the parts there

In the Top of the right sidebar under “Color Palette”, click on the dropdown with the color name in it. This dropdown will show only the colors that the selected parts have in common.

You will have to check the “Hide unavailable colors” checkbox in this dropdown to make it work.


can someone identify this lego character for me?

this appears to be
Robot Devastator 4 - Red Eyes

from the following sets

8101-1:Claw Crusher
or
8107: Fight for the Golden Tower
or
8112: Arachnoid Stalker or 8115: Dark Panther

Partlist for Devastator

Bricklink part list