Let's Make Robots!

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)

TX2 RX2 Pin Assignments

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.

TX2 RX2 document Link

RC Car Arduino Code Link

Video coming soon... Video added.


Image before I took the RC apart

Before1  Before2

Full Picture

Full1

 

Ping Sensor & RX2 Connection

 

RX2 Front & Back

RX2Front RX2Back

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.
Bajdi's picture

Looks like a cheap base to experiment with robotics. I've thought about it myself, to buy a big 4WD RC car and use that as a base for an outdoor robot.

targetdg15's picture

RC cars make amazing bodies for robots! However i would make one suggestion, always buy them second hand. There is no pressure to do it right the first time if you got the RC truck at Goodwill or Salvation Army. I once bought a new version of the Rebound (an RC car that flips over) and burned out a motor.... total waste!

Dan M's picture

Great job.

In the video, it looked like it has a tendancy to turn to the right (unless you intentionally did that). Since that is a premade chassis, it may have an adjustment underneath; a mechanical adjustment in the steering linkage to center the steering. Otherwise, you might need to correct that in software.

nintwala's picture

yeah, I intentionally did that! wanted to make it look like it was drunk! lol... just kidding. Yes, there is an adjustment underneath to fine tune the center of the steering. I just didnt have it adjusted at the time of the video.

ignoblegnome's picture

Nice post. You've almost got enough detail for a good walk through post. ; j

targetdg15's picture

Love the simplicity of it all. I too found it much easier to just use the onboard chip rather than setting up my own system.