The Wii Nunchuck adapter is a small PCB that adapts the Wii Nunchuck connector to standard 4-pin header. It plugs directly into the Arduino, no wiring necessary.

One of the coolest things about the Wii is that the expansion port on the bottom of the Wii remote is an I2C serial connection. This means that anything that plugs into that port can work with microcontrollers like the Arduino or Basic Stamp or others. Of the available peripherals, the Wii Nunchuck is one of the best. It contains a 3-axis accelerometer, a 2-axis joystick, and two buttons. Hooking up a Wii Nunchuck to Arduino is easy - see the notes and libraries below.

This “wiichuck adapter” let’s you play with the Wii Nunchuck and other Wii remote peripherals without needing you to cut cables. Just plug it into the Wii Nunchuck, then into the Arduino, in to Analog In pins 2,3,4,5. Pins 4&5 are the I2C communication pins and Pins 2&3 can act as the power supply for the Nunchuck.

Please note that this is JUST the board, and to plug it it to Arduino headers (for example) you may need to solder on some Pin Headers (Male).

Resources

• nunchuck_funcs.h
• WiichuckDemo
• Wiichuckdemo.zip (all zipped up)

It is based off the original research done by Chad Philips of Windmeadow Labs. The library uses the Wiring I2C library called “Wire”. This library is built-in to Arduino, as long as you have the latest Arduino development environment. To see another Arduino sketch using this library, you can check out the BlinkMChuck example that’s part of the BlinkM examples.

The library functions are:

• nunchuck_init() — init a nunchuck connected to an Arduino
  
• nunchuck_init_with_power() — init a nunchuck plugged directly into an Arduino on analog pins 2,3,4,5.
  
• nunchuck_get_data() — get a data packet from the Nunchuck

Then you can get at the data packet using various helper functions like:
nunchuck_accelx() — get X-axis acceleration
nunchuck_zbutton() — get Z-button state
…and so on, see the header file for a complete list

Nunchuck Information

- Wiimote/Extension Controllers/Nunchuk — info page about the Nunchuck on WiiLi (Linux for Wii) site
“Wiimote Accessory Bus” — docs about the Nunchuck’s connector.