Line Tracking Robot

While surfing around the internet one evening, I was drawn into an ad on Facebook for a product from Banggood.com. It was a video clip of a small robot following a line, a DIY kit for under ten bucks! See HERE.

While it wasn't really a good kit for a small child to do, I thought it would be fun to do it together, and great to play and explore with later too.

When I first saw it, I thought it must run on a little micro (like ATtiny), and after looking at the site, I discovered it was a set of op-amps. This helped to get me excited, mostly because I dislike this online trend where everyone just throws a microcontroller at all of their problems.

We have a few things here that I like:
Things that blink!
Things that move!
Op-amps!
Transistors!


The circuit design is simple enough, and was easy to solder together. One issue I had was that none of the kit was in English, but anyone who is into hobby electronics should be able to put this thing together without much trouble. This does seem like it is intended to be an educational kit, as it has lots of cool information about the various parts.... which I can't read, but they look good.

So basically between the pictures online and the schematic, I was able to assemble it. The motors don't come with wires already on them, I used the slack from the battery pack to make wires to go from the motor terminals to the PCB, no issues with that whatsoever.

I also had a little difficulty soldering the photo-sensor and LED's onto the board backwards, as they need to be left long and sticking out so
they're close to the surface the robot drives on. I'm not sure if a distance is specified in the instructions, but I simply left the leads as long as they could be, and it seems to work just fine like that. The tubes on the photo-sensors also appear to be heat shrink, I've just left them as they were without shrinking them, and that seems fine too.

Precision resistors are also a little different than what you may normally have. They have three digits with a multiplier behind it, so the 3.3K resistor is banded as orange orange black red (330 plus 2 zeros on the end or 33000 ohms), rather than orange orange orange (33 plus 3 zeros or 33000ohms)... geh, you'll figure it out I'm sure!

One packing issue was that all the parts were dumped into one bag together, but it did cause the op-amp to somehow get stuck inside of the spring on the battery holder. I needed to carefully remove it with a pair of tweezers. All the parts were there, and nothing was broken, but I am a fan of bags for little bits. Anyway, here are a bunch of pictures of the building process.

And that's about it! If you have any questions, type them in below. Follow the link, get a kit and have some fun. You can't put the parts together for that price tag, even if you decide to do something else with the parts, it's still a great deal. The kids liked the project and are still playing with the robot.