/* This program is designed to allow two Wii Nunchucks to operate on the same I2C bus
by the use of 2 BJT transisters. This file includes a demenstration of each nunchuck
controlling their own LED by use of their z_button (made with arduino - 0010 Alpha), circuit schematic can be found at this forum:
http://www.wiimoteproject.com/tech-chat/2-nunchuck-with-arduino-help/
Nunchuks operate off of 3v3 supplied by arduino
First Few lines of twi.h edit...
#define ATMEGA8
#ifndef CPU_FREQ^M
#define CPU_FREQ 16000000L
#endif
#ifndef TWI_FREQ^M
#define TWI_FREQ 100000L
#endif
found at:
http://www.windmeadow.com/node/42
have fun
bd
(aka:johnnyonthespot)
*/
#include <Wire.h>
#include <string.h>
#undef int
#include <stdio.h>
uint8_t outbuf1[6]; // array to store nunchuck1 output
uint8_t outbuf2[6]; // array to store nunchuck2 output
int cnt = 0; // count to make sure 6 bytes are received from nunchuck
int nunPin1 = 8; // Digital pin to select nunchuck1
int nunPin2 = 9; // Digital pin to select nunchuck2
int led1 = 2; // Pin connected to LED1 (turns off when nunchuck1's z_button is pushed
int led2 = 3; // pin connected to LED2 (turns off when nunchuck2's z_button is pushed
int state = LOW; // keeps tabs on which nunchuck is being read (Low = n1, High = n2)
void
setup ()
{
pinMode(nunPin1, OUTPUT);
pinMode(nunPin2, OUTPUT);
pinMode(led1, OUTPUT);
pinMode(led2, OUTPUT);
digitalWrite(nunPin1, HIGH); // both nunchucks must start out high
digitalWrite(nunPin2, HIGH); //in order to initiate both at once
Wire.begin (); // join i2c bus with address 0x52
nunchuck_init (); // send the initilization handshake
}
void
nunchuck_init ()
{
Wire.beginTransmission (0x52); // transmit to device 0x52
Wire.send (0x40); // sends memory address
Wire.send (0x00); // sends sent a zero.
Wire.endTransmission (); // stop transmitting
}
void
send_zero ()
{
Wire.beginTransmission (0x52); // transmit to device 0x52
Wire.send (0x00); // sends one byte
Wire.endTransmission (); // stop transmitting
}
void
change_nunchuck() // Swaps between nunchucks
{
if (state == LOW)
{
digitalWrite(nunPin1, LOW);
digitalWrite(nunPin2,HIGH);
state = HIGH;
}
else
{
digitalWrite(nunPin1, HIGH);
digitalWrite(nunPin2,LOW);
state = LOW;
}
}
void
loop ()
{
Wire.requestFrom (0x52, 6); // request data from nunchuck
while (Wire.available ())
{
outbuf1[cnt] = nunchuk_decode_byte (Wire.receive ()); // receive byte as an integer
cnt++;
}
// If we recieved nunchuck1's 6 bytes, then go get nunchuck2's data
if (cnt >= 5)
{
cnt = 0;
change_nunchuck ();
send_zero ();
delay (10); // This is necessary to ensure communication goes well
Wire.requestFrom (0x52, 6); // request data from nunchuck
while (Wire.available ())
{
outbuf2[cnt] = nunchuk_decode_byte (Wire.receive ()); // receive byte as an integer
cnt++;
}
}
// if we received nunchuck2's 6 bytes, then output z_button status through LEDs
if (cnt >= 5)
{
print ();
change_nunchuck();
}
cnt = 0;
send_zero (); // send the request for next bytes
delay (10); //required
}
// Print the input data we have recieved
// accel data is 10 bits long
// so we read 8 bits, then we have to add
// on the last 2 bits. That is why I
// multiply them by 2 * 2
void
print ()
{
//Nunchuck1's Data
int joy_x_axis1 = outbuf1[0];
int joy_y_axis1 = outbuf1[1];
int accel_x_axis1 = outbuf1[2] * 2 * 2;
int accel_y_axis1 = outbuf1[3] * 2 * 2;
int accel_z_axis1 = outbuf1[4] * 2 * 2;
int z_button1 = 0;
int c_button1 = 0;
//Nunchuck2's Data
int joy_x_axis2 = outbuf2[0];
int joy_y_axis2 = outbuf2[1];
int accel_x_axis2 = outbuf2[2] * 2 * 2;
int accel_y_axis2 = outbuf2[3] * 2 * 2;
int accel_z_axis2 = outbuf2[4] * 2 * 2;
int z_button2 = 0;
int c_button2 = 0;
// byte outbuf1[5] and outbuf2[5] contains bits for z and c buttons
// it also contains the least significant bits for the accelerometer data
// so we have to check each bit of byte outbufn[5]
if ((outbuf1[5] >> 0) & 1)
{
z_button1 = 1;
}
if ((outbuf1[5] >> 1) & 1)
{
c_button1 = 1;
}
if ((outbuf2[5] >> 0) & 1)
{
z_button2 = 1;
}
if ((outbuf2[5] >> 1) & 1)
{
z_button2 = 1;
}
//Lights up corrosponding LEDs
if (z_button1 == 1)
{
digitalWrite (led1, HIGH);
}
else
{
digitalWrite (led1, LOW);
}
if (z_button2 == 1)
{
digitalWrite (led2, HIGH);
}
else
{
digitalWrite (led2, LOW);
}
}
// Encode data to format that most wiimote drivers except
// only needed if you use one of the regular wiimote drivers
char
nunchuk_decode_byte (char x)
{
x = (x ^ 0x17) + 0x17;
return x;
}
