WiiChuck adapter. Solder 4 pins onto the unit. Do it backwards from this picture and you will more easily see the silkscreened pin IDs when the unit is on a breadboard.
"+": either VCC (on a 3.3V arduino), or 3.3V (on a 5V arduino)
"-" - GND
"d" - SDA (A4 on Pro Mini)
"c" - SCL (A5 on Pro Mini)
Note: Pro Mini I2C pins are SDA (A4) and SCL (A5).
ArrBot Nunchuck Tester. Open the serial monitor. Move the joystick, press the buttons, and shake the Nunchuck along all three axes. You'll see current, max, and min values. We'll use those later to calibrate.
Note: There are a ton of aftermarket nunchucks and counterfeit units being marketed as from Nintendo. A lot of the clones and counterfeits don't work. My genuine nunchuck works well, and comes with a little instruction label attached to the cable. If your nunchuck fails to produce good values in this program return it and get an authentic unit. Good Luck, even on Amazon there are plenty of counterfeits being sold as Nintendo units. :( :( :(
TODO: library setup
TODO add screen shot of program running.