Here’s something I made for fun a couple months ago and I need to make it again soon so I’m posting schematics and Source code for anyone to download and make their own fun toy with Arduino.

Parts list:

Arduino Uno

Original Wii Nunchuck

Nunchuk to Arduino adapter (link below)

Laser pointer

2 mini Servos

You can buy an adapter here :

http://todbot.com/blog/2008/02/18/wiichuck-wii-nunchuck-adapter-available/

We are using the Wire library for I2C communication with the Nunchuk. See this reference where the I2C pins are on your Arduino: http://www.arduino.cc/en/Reference/Wire. On Arduino Uno the I2C pins are A4 and A5.

See schematics for more details on how to connect the components.

[code lang=”arduino”]

#include <Wire.h>

#include <string.h>

#include <stdio.h>

uint8_t outbuf[6];

int cnt = 0;

int ledPin = 13;

int laserPin = 12;

int servoPin = 9;

int servoPin2 = 10;

int pulseWidth = 0;

int pulseWidth2 = 0;

long lastPulse = 0;

long lastPulse2 = 0;

int z_button = 0;

int c_button = 0;

int refreshTime = 20;

int minPulse = 1000;

int minPulse2 = 500;

int dtime=10;

#define pwbuffsize 10

long pwbuff[pwbuffsize];

long pwbuffpos = 0;

long pwbuff2[pwbuffsize];

long pwbuffpos2 = 0;

void setup()

{

Serial.begin (9600);

Wire.begin ();

nunchuck_init ();

pinMode(servoPin, OUTPUT);

pinMode(servoPin2, OUTPUT);

pinMode(laserPin, OUTPUT);

pulseWidth = minPulse;

pulseWidth2 = minPulse2;

Serial.print ("Finished setupn");

}

void nunchuck_init()

{

Wire.beginTransmission (0x52);

Wire.write (0x40);

Wire.write (0x00);

Wire.endTransmission ();

}

void send_zero()

{

Wire.beginTransmission (0x52);

Wire.write (0x00);

Wire.endTransmission ();

}

int t = 0;

void loop()

{

t++;

long last = millis();

if( t == 1) {

t = 0;

Wire.requestFrom (0x52, 6);

while (Wire.available ()) {

outbuf[cnt] = nunchuk_decode_byte (Wire.read ());

digitalWrite (ledPin, HIGH);

cnt++;

}

if (cnt >= 5) {

// printNunchuckData();

int z_button = 0;

int c_button = 0;

if ((outbuf[5] >> 0) & 1)

z_button = 1;

if ((outbuf[5] >> 1) & 1)

c_button = 1;

switch (c_button) {

case 1:

switch (z_button) {

case 0:

digitalWrite(laserPin, LOW);

muovi();

break;

case 1:

digitalWrite(laserPin, HIGH);

muovi();

break;

}

break;

case 0:

switch (z_button) {

case 0:

break;

case 1:

//delay(3000);

break;

}

break;

}

}

cnt = 0;

send_zero();

} // if(t==)

updateServo();

delay(dtime);

}

void updateServo() {

if (millis() – lastPulse >= refreshTime) {

digitalWrite(servoPin, HIGH);

delayMicroseconds(pulseWidth);

digitalWrite(servoPin, LOW);

digitalWrite(servoPin2, HIGH);

delayMicroseconds(pulseWidth2);

digitalWrite(servoPin2, LOW);

lastPulse = millis();

}

}

int i=0;

void printNunchuckData()

{

int joy_x_axis = outbuf[0];

int joy_y_axis = outbuf[1];

int accel_x_axis = outbuf[2]; // * 2 * 2;

int accel_y_axis = outbuf[3]; // * 2 * 2;

int accel_z_axis = outbuf[4]; // * 2 * 2;

int z_button = 0;

int c_button = 0;

if ((outbuf[5] >> 0) & 1)

z_button = 1;

if ((outbuf[5] >> 1) & 1)

c_button = 1;

if ((outbuf[5] >> 2) & 1)

accel_x_axis += 2;

if ((outbuf[5] >> 3) & 1)

accel_x_axis += 1;

if ((outbuf[5] >> 4) & 1)

accel_y_axis += 2;

if ((outbuf[5] >> 5) & 1)

accel_y_axis += 1;

if ((outbuf[5] >> 6) & 1)

accel_z_axis += 2;

if ((outbuf[5] >> 7) & 1)

accel_z_axis += 1;

Serial.print (i,DEC);

Serial.print ("t");

Serial.print ("X: ");

Serial.print (joy_x_axis, DEC);

Serial.print ("t");

Serial.print ("Y: ");

Serial.print (joy_y_axis, DEC);

Serial.print ("t");

Serial.print ("AccX: ");

Serial.print (accel_x_axis, DEC);

Serial.print ("t");

Serial.print ("AccY: ");

Serial.print (accel_y_axis, DEC);

Serial.print ("t");

Serial.print ("AccZ: ");

Serial.print (accel_z_axis, DEC);

Serial.print ("t");

Serial.print (z_button, DEC);

Serial.print (" ");

Serial.print (c_button, DEC);

Serial.print ("rn");

i++;

}

char nunchuk_decode_byte (char x)

{

x = (x ^ 0x17) + 0x17;

return x;

}

void muovi (){

float tilt = (700 – outbuf[3]*2*2);

float tilt2 = outbuf[2]*2*2;

tilt = (tilt);

pulseWidth = (tilt * 5) + minPulse;

tilt2 = (tilt2-288);

pulseWidth2 = (tilt2 * 5) + minPulse2;

pwbuff[pwbuffpos] = pulseWidth;

pwbuff2[pwbuffpos2] = pulseWidth2;

if( ++pwbuffpos == pwbuffsize ) pwbuffpos = 0;

if( ++pwbuffpos2 == pwbuffsize ) pwbuffpos2 = 0;

pulseWidth=0;

pulseWidth2=0;

for( int p=0; p<pwbuffsize; p++ ){

pulseWidth += pwbuff[p];

pulseWidth2 += pwbuff2[p];

}

pulseWidth /= pwbuffsize;

pulseWidth2 /= pwbuffsize;

}

[/code]

You can download all code here :

WiiChuck Source code and schematics

Or Get it on Github (improvements welcome!):

https://github.com/msurguy/arduino-wiichuck-laser