Controlling 4 Motors

This may be a newbie Arduino/Robotics question:

I am looking to to build a 4 wheeled robot that can drive around outdoors. I have been looking at the Devantech RD02 [1] system (motor controller + 2x 12v-DC motors). It offers Arduino support but the controller that comes with the RD02 can only drive 2 motors at a time, thus I would need 2 RD02's.

However; I currently have an Arduino Uno which only has 1 set of serial/I2C pins, which are needed to communicate with the motor controller.

My question is:

What suggestions does everyone have on how I can go about controlling 4 motors rated for outdoor use. What motors? What motor controllers? Arduino Uno or Mega?

Any help would be greatly appreciated!! Thank you! :slight_smile:

[1] http://www.robotshop.com/en/drive-system-12-volt.html

I2C is a bus. All devices on the bus share the SCL and SDA pins. Each device on the bus has a unique address. Up to 128 devices can (theorecally) share those 2 pins. Motor driver I2C instruction.

Thanks for the reply!

So each motor controller can control only 2 motors max. It sounds like I should be able to wire 2 separate controllers to the I2C bus? Am I understanding that correctly?

Yes. According to the linked page, you connect one board and set its address (if necessary), then disconnect it and connect the other. Set the second to a different address. Connect both to the bus and control each via its unique address. There is more to it but that is the basics. The page explains it all. Or there are jumpers to change from the default addres.

I2C information

Handy I2C scanner
to verify addresses and communication.