If you need a very powerful robot controller, take a look at RoboPi
- tested and supported with Raspberry Pi Models A / A+ / B / B+ / 2B
- RoboPi is based on an 8 core 32 bit RISC microcontroller
- 24 flexible I/O's (each I/O can be configured as digital input, digital output, servo output, pwm output, ultrasonic range sensor input)
- 8 channels of 12 bit analog input
- all I/O's use 3 pin servo style headers
To program RoboPi, you can use the easy to use C/C++ and Python RoboPi libraries.
You can download the assembly manual and user manual from the product page to see if it suits you.
Here is a link to a simple robot built with RoboPi, including sample Python code:
I'll be updating my Elf article soon, as I just added a Pi camera to Elf!