Introduction: Simplest Line Follower
This is an Easy Line Follower ..
Which is based on simple schematics only
just follow some instruction and make it is is very simple..
Step 1: Making PCB
Last week I finally got time to do a bit of work. I made my own PCB :). I wish I had learned this back in college. It have would saved me so much time. What PCBs did I make? The line follower circuit (Click me to open tutorial). This robot uses very little wiring. None of the wires have been soldered. I have also replaced the mounts for the sensors. I will describe everything in today’s post.
Before we begin, you’ll need to know how to design and build your own PCBs. A friend of mine has written excellent, very well explained tutorials for this. He uses Eagle. I will try learning KiCad for you free software folks. I’m having trouble with it though (Do pop in a comment if you would like to help me out)
link are below
I would suggest going over his circuit if you need some confidence. I
made the line follower circuit for my first PCB. It’s simple too so you could try that as your first PCB.
Assuming you know how to make PCBs, here’s what you do. Make one main PCB for the L293D. You’ll need two other small PCBs to put the sensors. I’ve uploaded the eagle files containing my designs. You can download these from the Box.net widget on the right sidebar. Look for bruno-eagle-files.zip and LEDLDR-eagle-files.zip. I would suggest designing the PCB yourself for practice. Your design may be much better. I have a lot of inconsistencies in mine.
Here are photos of my PCBs:
The main L293D PCB:
Step 2: Placing the Component
So those are the boards. Also remember to drill holes for the main PCB. I
forgot to do this till the end. Drilling after soldering is a pain. Next step is to solder the components. Check all connections with a multimeter. At this point you can even check if the LEDs are lighting up and if the LDR sensors are working. Remember – do not plug in the chip till you have done this bit of testing. After you’ve checked that all the voltages are right, put a protective coat over the copper side of the PCB. I used lacquer spray. Unfortunately I forgot it is acetone based and made a mess of the labelling of the L293D PCB. Here is how it all looks now:
Step 3: Making Sensors
As you can see, I should have left a little more space at the edges. The
copper in the photo is tarnished. It took a while for me to buy lacquer so this happened by then. A bit of sandpaper got it all cleaned up. My suggestion is to put the protective coating soon after you’re done soldering. Note that I have used berg pins instead of soldering the wires directly. Here is how I soldered the sensors:
Step 4: The Chassis
Now that the electronics is mostly done, lets move on to the chassis. I
used the same mechano plate as last time. For the sensors, I also used a mechano part. Note a few differences in the photos you are going to see and the actual robot. The photos below shows the 4-hole part. I replaced this with a 5-hole one later. Also I moved the PCB up to the front as the wires weren’t long enough. Finally I had to change the wheels as this construction was very unstable. You’ll see the corrections in the last photo. For the connections, I used female jumper wires such as these
Before fixing the PCBs to the base, make sure you put something to
protect the copper side. We do have a coating but better be safe than sorry. I used pieces of cardboard.