Car Chronicles

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 One of the first real projects I ever completed was an RC car. As a 13 year old with no money, I did not have a 3D printer at the time. I guess cardboard will have to do.


This "Mark Zero" iteration was not much more than a breadboard and a few motors taped to a piece of cardboard. Using a salvaged infrared sensor and a TV remote, I was able to communicate with the device from afar. An Arduino Nano set in the breadboard recorded different keypresses so I could associate them with moving the motors in different sequences. A servo motor in the front rotated a set of wheels spinning in a straw, while a small motor in the back drove a gearbox to propel the rear wheels. After this project, I got a 3D printer for Christmas. So I immediately started on the next iteration.

This one was 3D-printed. It also used a 2.4GHz nRF24L01 radio module, and an STMF103 dev board. 3D printing opened a huge number of possibilities, though I'll be the first to admit I was not able to use its full potential at first. Somehow this iteration was significantly less powerful than my cardboard version, likely due to my stubbornness in using 3D printed gears. It's quite difficult to get the mating distance just right using toothpicks as axles. The rubber band driving the wheels also slipped quite often.
As tryouts for my local robotics team were starting soon, I needed a way to prove a sophomore with no prior experience could join the club. And so the third iteration was conceived. This was made in less than a week as the deadline was soon. It seems that this pressure ended up helping, as this was my best iteration yet. Using a worm gear to drive the car allowed for a large gear reduction in one stage, but meant the wheels were not backdrivable. 3 AA batteries were required for this car as the servos needed at least 5v. This was not ideal but it worked.

To drive this radio module, an improved remote was also made. Using one AA battery and a boost converter module, I was able to step the voltage up to 5v, then drop it to 3.3v with an LDO (wasteful, I know). The joysticks were absolutely terrible, and are the reason why I went all out with the new remote. I'll write a post on that remote soon.

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