A long time ago I bought a cheap RC car to experiment with. I figured I could use its two-motor tank-drive in another application- I wanted to see if i could re-purpose the circuit for something completely different (I considered an RC door lock for a while, but never got around to it). I also wanted to mess around with the Infrared “transmitter” and find some application for that too- I didn’t find one, but I did learn a lot. Here’s what I discovered.
The circuit board was relatively simple- the motor inputs were on the left and right sides, and the infrared sensor is by the charging port. The battery is a 100mah LiFe that charges directly through the board from the transmitter. I was planning on using a phone charger wall-wart to charge the battery by swapping connectors, but I took it apart and salvaged the motors instead; I didn’t think the car was going to last very long anyway.
Circuit board with motors and battery still attached. I might have used the IR sensor for something, but at the time I didn’t know if that was possible or not, nor did I know how to use it for anything.
The motors are similar to the kind you might find in a cell phone for vibration. I had some gears from a wristwatch that press-fit snugly onto the shaft, so I played around with making a set of gearbox plates, but I got bored of that pretty quickly. You can check out my post on that, too.
I’m always amused by the batteries that manufacturers throw into these toys. Before I came across this RC car, I’d never seen a LiFe battery before, so they were new to me. A quick search online told me that they were basically bad LiPOs- they don’t hold their charge as long, can’t deliver current as efficiently, and don’t last very long. They are cheap in comparison to LiPos, however, which is a plus.
I have since thrown the board away, but I still have the motors- I’m considering building a gearbox driven by one of them to turn a 5” propeller that’s collecting dust.
DIY Robotics 