Today on Creativity Hero Channel I'm
going to make an interactive LED coffee
table. This unique coffee table can
create beautiful atmosphere and will be
real focal point in my living room. I
wanted to make a simple design with some
interesting features that will take my
room to a whole new level. It is
controlled via a custom-made Android
application so I can easily change the
reactive color, or the background color,
and I can even adjust the brightness. The
table is made out of MDF for the box, a
pine for the legs, a glass top, and its
inner part consists of an Arduino board,
a Bluetooth module, some LEDs, proximity
sensors, and a bunch of wires. This is a
very challenging project, but with hard
work and patience anyone can build it. Here I'll show you the entire process of
building, wiring, and connecting all the
pieces together. Now let's start with the
build. First I'm cutting all the pieces
to size on my table saw. I'm going to
make a box out of MDF. I'm using a 10
millimeters thick MDF for the sides and
the 8 millimeters thick MDF for the
bottom. Most of the pieces I cut using my
table saw fence, but for the larger
pieces I clamped down a scrap wood
as a guide, because the fence is pretty
wide and couldn't be secured to my
workbench. Inside the box I'll create a
grid out of MDF, so I need to cut 12
pieces 4 centimetres wide. For the legs
and the frame below the box I used a
large pine board. You can notice that it
is warped, but I don't have a planer
which means I need to make a lot of cuts
and adjustments on the blade and the
fence in order to flatten all the pieces.
It took me some time until I finished,
but finally I got nice and smooth strips
all with the same width. To cut all the
pieces to the right length
I used the crosscut sled. For making
repeated cuts I mounted a stop block.
Some of the pieces were much longer and
I needed to make another stop block. I
set the fence and clamped a scrap of
plywood on it, which will actually serve
as a stop block for the longer pieces.
For the grid that I previously mentioned
I should make dadoes onto each MDF piece so that they can easily lock together
and make a perfectly squared grid. So, I
marked all the points for the dadoes,
wrapped the pieces together with a
masking tape, set my blade on the
appropriate height, and made all the cuts.
They were very easy and fun to make. All
the dimensions for this table can be
found in the video description. There I
also put links to all the tools and the
materials needed for this project. Once
I'm done with all the cuts I can move on
to sanding. I started with 80 grit
sandpaper and then continued with 120
grit until everything was nice and
smooth.
First I assembled the box. I applied a
nice amount of wood glue and joined the
pieces together with corner clamps and a
band clamp to make stronger connection.
Between the sides of this frame I added
a small piece of wood in each corner and
secured them well. After that, I can secure
the bottom of the table with a wood
glue and a lot of screws to make sure it
is firmly attached. I pre-drilled holes
and then inserted countersunk screws.
In order to avoid any gaps I'm applying
a wood filler on the joining parts of
the table. While the wood filler was
drying I made two openings on the bottom
of the table, one for the high voltage
cable and other for the switch. Using a
rasp I made the opening for the switch a
perfect fit. When I placed the smaller MDF
board into this box I noticed that it
was warped in the middle due to its
length, so I added two more small wooden
pieces into the box for better support.
Then I measured the depth of the box and
also realized that I should add extra
8 millimeters height onto those
small wooden pieces so that when I
finally place the glass on the top it
would be
flush with the sides. Fortunately I had
8 millimeters thick MDF,
which is perfect for this purpose. I cut
six small pieces of it and glued them on
the top of the pieces that I previously
attached. I fine-sanded the MDF to
remove the extra wood filler and prepare
it for painting. Then, I wiped the dust off
of the surface with a wet rag. I don't
have to paint the entire inner part of
the table, so I applied a masking tape on
the sides to get straight, clean paint
lines. After that I applied an oil-based
primer using a roller for large surfaces
and a brush for the areas that are hard
to reach. I left it to dry overnight and
sanded the surface with my orbital
sander using 120 grit sandpaper. Now it
is time to apply paint. I chose an
oil-based white paint and carefully
applied it on the surface making sure I
cover every part of the table. While it
was drying I moved on to the legs and
the frame below the table. I will join
them together with pocket hole screws.
The pocket hole jig that I have is very
useful and easily adjustable tool for
making pocket holes. I wasn't able to
make two pocket holes on each side due
to the width of the strips, but later I
can mount corner brackets if needed.
Before attaching the screws, I'm applying
a wood glue for stronger connection. then
I'm driving the screws in. In order to
make the pocket holes invisible I
inserted the screws on the top of the
frame. It was a bit complex step because
everything has to be square but I
succeeded with a little effort
and focus on my work. Again, I applied a
wood filler into the gaps and left it to
dry. Then, sanded the excess to prepare
it for staining. When it comes to the
stain, I applied a rosewood stain to
get a nice contrast between the top and
the legs. I did the same in my previous
project and it turned out wonderful. All
the pieces that will be used for the
grid inside the table I painted white as
well. What's left to do is to
join the two parts of the table together.
I clamped the top with the bottom,
pre-drilled holes with a countersink
drill bit, and then used a lot of screws
to secure them together. OK, now I can
move on to the electronics part. The
electronic parts that I'm using are
addressable LEDs, infrared proximity
sensors, an Arduino Mega board, a
Bluetooth module, 5V power supply,
and a bunch of wires. So, first I'm using
this template to drill three holes into
each square and onto each square I will
insert an LED and a proximity sensor
and connect them with some wires. I will
attach everything onto this MDF board. It
will be divided into 45 squares. Then, I
cut 45 LEDs into individual pieces. From
this strip I need to cut 5 centimeters
long pieces of red and black wire and
strip off around 5 millimeters of the
insulation on their ends. I'll use one
pair of those for each LED and another
pair for each proximity sensor. I'm doing
the same with this green wire, but here
I'm cutting longer pieces and also
stripping off their ends. Then, I am
soldering the wires onto the LEDs. The
black and the red I am soldiering on the Ground and the 5V pad,
and the green one in the
middle, or the Data IN pad. After that,
I can move on to the proximity sensors. I
separated the Infrared transmitter and
the receiver and made a larger distance
between them. In a normal position the
sensor won't be able to detect the glass
on top of the table, because the glass
won't reflect the Infrared light. In this
way, I can position the transmitter and
the receiver at an angle so that the
light can be reflected to the receiver
on the other side. So, I am removing the
transmitter and soldering it back on
the sensor, but this time with 4
centimeters long wires. I used single
core wires from an Ethernet cable,
because they can be easily bent and stay
in that position. On the other side of
the sensor I need to solder the black
and the red wire to the Ground and 5V pin, and a longer gray wire to the
Output pin that will connect
sensor to the Arduino board. These are
pin headers that I need to solder onto
the longer wire ends, so they can be
easily inserted into the Arduino board. To
insulate them I'm using a shrink tube
and a lighter. I repeated this step 45
times. Here you can see all the LEDs and
the sensors ready to be attached onto
the MDF board. The LEDs are the first to
be attached onto the board. I inserted
them into the holes that I previously
drilled, peeled off the tape cover on the
back and stuck them onto the board. Then,
I connected them by soldering the green
wire in the middle of each LED or the
data OUT pad of the previous led to the
data IN pad of the next LED. Once I'm
done with the LEDs I'll do the same with
the proximity sensors. This time I'll hot
glue them next to the LEDs. Here I need
to pay attention to the length of the
gray wires. All of them will be inserted
into the Arduino board, which will be
positioned in the middle of the back side
of the board. So, the cables that are
further from the Arduino board
are longer, and as they're coming closer
to it, they become shorter. Yyou can find
the exact dimensions that I used on the
website article. The Infrared transmitter
and the receiver
need to be placed facing up, so I'm
making some adjustments here. Now, I will
turn the MDF board to the back and
connect all the wires. I'll start with
hot gluing copper wires along with the
length of the board. They will be used as
power lines for the LEDs and the
proximity sensors. On the first line
I'll solder all the red wires and on the
other line all black wires. Before
soldering, I need to remove the
insulation off of the copper wires with
a sandpaper, otherwise I won't be able
to solder them.
It took me a long time until I
finished soldiering all the wires. At the
end, I connected all the positive and all
the negative lines. Also, on these lines I
soldered two more wires which I'll later
connect to the power supply.
I added 330 ohms resistor between the
first LED and the Arduino to reduce the
noise on that line. All the wires are
ready, so I carefully insert them into
the Arduino board in order. Here I'm also
inserting the Bluetooth module. This is
the complete circuit schematic where you
can see how I connected everything
together. For more details on how to use
the Arduino in combination with this
addressable LEDs and the Bluetooth
device you can check Dejan Nedelkovski
YouTube channel and his website HowTo
Mechatronics.com. He made a tutorial on
how everything works, including the
source code of the program and the
custom-built Android application. I'll
put a link to his video and article in
the description below. Dejan makes awesome videos in the area of Mechatronics,
providing complete explanation, circuit
schematics and source codes. Before
mounting the power supply, I made a
continuity test on the circuit using a
multimeter. The multimeter didn't beep
which meant my connections were all good.
now that I'm done with it,
I can mount the 5V power supply on
the bottom of the table. It needs to be
raised up just a little to get better
air flow.  Therefore, I glued two pieces of
MDF and placed the power supply above
them. Then, I pulled the switch in and the
main power cord into the appropriate
holes, and connected them to the power
supply. 4 meters of the cord is enough
for my space, so I cut it to size and
wired aplug on its end. After that, I
brought the MDF panel and connected the
last two wires into the power supply. At
this point, we're ready to program the
Arduino. The code is fairly simple, it
just reads the proximity sensor and if
an object is detected it lights up the
particular LED. For the color and
brightness control we use the
custom-built Android application. The
data coming from the smartphone is
received via the Arduino
Bluetooth module. As I mentioned earlier,
you can find detailed explanation on how
this code works on Dejan's article. Once I
uploaded the code I placed the panel
inside the table. I noticed here that the
power indication LED of the proximity
sensors would interfere with the main
LED light, so I covered them with an
electrical tape. Making the grid is very
easy, I just need to lock all the parts
together, and as you can see they fit
snugly. Finally I can put the matte glass
on the top of the table, turn the switch
on and check if everything works
properly. One of the LEDs doesn't turn on
when I place a glass on top of it, so I
removed the glass and adjusted the
transmitter. It needs to be positioned at
a right angle to be able to reflect the
light to the receiver. Now I can say that
I'm finally done with this project.
This interactive coffee table turned out
perfect. I like every part of it,
including the design, the color change and
the brightness adjustment. It gives
another dimension to my living room.
Thanks for watching. I hope you enjoyed
this amazing DIY project. If you like
this video give me a thumbs up, leave a
comment down below and subscribe to my
channel.
