Monthly Archives: March 2012

Arduino: RC Car

I had bought a RC Car from walmart for about $15 to use with the Arduino Motorshield a while back (see here). Fortunately, I had taken some pictures before I removed the RC receiver circuit from it. Turns out that its lot more efficient to use the onboard controller along with an Arduino instead of using a motorshield. I didnt some research and found out that many “cheap” RC cars use the same Realtek TX2 & RX2 chips inside. I was lucky enough to find the same inside this RC car.

I was able to connect 5 wires to the Arduino and control the car by sending a HIGH signal directly to the RX2 chip. Here are the in assignments.

Arduino      RX2
Ground           PIN2 (GND)
PIN 13            PIN11 (Forward)
PIN 12            PIN10 (Backward)
PIN 11            PIN6 (Right)
PIN 10            PIN7 (Left)

The 2 motors and the RX2 circuit is powered by 3xAA batteries in the car itself and the Arduino UNO was powered by a 9V battery. I also decided to add a PING sensor to make the car backup automatically when it comes close to something. The code is not perfect as you can see in the video, but it can be modified later.

TX2RX2.doc (Realtek TX2 & RX2 info)

CarBotPing.pde (Arduino Code)


Solar Spinner BEAM Bot

I have been doing some BEAM bot work on the side. Nothing exciting but I wanted to keep making them to get some practice/experience for future projects with solar circuits. This is basically a replica of the solar spinner thats posted here. It uses a Miller Solar Engine with a little modification.

Update: Added a timing capacitor (10uF) between pin 2 and 3 of the voltage trigger. Seems to work a lot better now.