Bus Pirate I2C Wiimotion Plus

Since I made my little Atmega16 avr development board I wanted to make a program to read out a Wiimotion Plus which I bought from Dealextreme for about 12 bucks. The Wiimotion Plus works with the Two Wire Interface (TWI/I2C) and since I already got the protocol working with an EEPROM chip I needed to do some investigation on this WM+. This wasn’t a big problem since I do have a Bus Pirate which is a super awesome tool for interfacing new chips without writing code! So I did not have to worry about writing code, I only had to try and find the right commands to put on the I2C communication line. So I played with the Bus Pirate and the WM+ for some time and found out that its real easy to interface the WM+.

My little AVR development board

About a month or 2 ago I decided a build a little development board for an atMega16 avr chip, because I didn’t want to build a breadboard for every single application. So with a friend of mine we made the schematic and designed a  board with a lot of pinouts for the most common used applications including serial communication, two wire interface (TWI/I2C), analog digital conversion, i/o (switches and leds), and some timer/counter pins.

The schematic and board;