Arduino and the motor driver

I spent several hours on surfing and reading to get a good overview on what's important when developing robots. So far I guess the most important rule is as follows: Keep it simple stupid!

Therefore I try to keep the mechanical design of my robot as simple as possible. Another interesting hint I've found is about the shape of the robot. If one has a differential drive robot it is a good idea to make it circle-shaped, because then it can rotate around its vertical axis without the risk to collide somewhere.

I also spent several hours on finding a good motor driver for my robot. I finally decided to buy the RD02 which is a complete robot driving set. It contains two wheels, two metal parts for mounting, two motors with(!) a sensor and the motor driver MD25. Although not very cheap this set is really worth the money, if you don't want to focus too much on the driveability of your robot. The MD25 does everything for you. For example you can set both motors to a certain speed and regardless of the momentum one motor is exposed to, it will try to keep up the same speed. This means that if you tell the motor driver to drive along a straight line, it will do that no matter if one motor spins easier than the other.

As  a microcontroller I chose an Arduino Mega ADK board. It is kind of over-kill for a robot of this purpose but it has one unique feature that already paid off. It has a USB host controller, which means that devices like a mouse, a keyboard or a game controller can be directly attached to the Arduino board. Beside that it also can be used to comunicate with an Android device.

The documentation of the MD25 is pretty good but there is more! The guys from robot electronics set up some example code to control the motor driver with an Arduino over a serial interface (which I used because of its very easy electronic circuit) or I2C interface.