Introduction: Arduino / Wii Controlled Lego Star Wars Rocket Turret
An Arduino board receives data from a Wii Nunchuck and sends it to hree servos: x, y and trigger. An independent laser has been added for targeting. Currently very wobbly because of the cheap servos used.
Step 1: Construction
The rocket turret was built using available Lego pieces around a "trigger" servo. A twitch of the servo when the Z button is pressed on the Wii nunchuck pushes the rocket trigger back, firing it. The base of the trigger servo is attached to x and y servos in a pan/tilt mechanism from Lynxmotion: http://www.lynxmotion.com/images/html/build153.htm
Step 2: Circuit
x axis servo on pin 6, y axis on pin 7, trigger servo on pin 8.
From the Wii nunchuck the yellow clock wire goes to analog in pin 5. Green data wire to analog in pin 4. red wire to 5v power via the breadboard with all the other power jumpers from the servos and white to ground.
9v battery to "vin" pin via an on/off switch.
The laser is not controlled by the Arduino. It is simply a laser attached to 3v battery pack via an on/off switch.
Step 3: Arduino Sketch
// Based on code from http://www.ideavirus.it/ adapted with help from Oliver at London Hackspace. Includes are: wire.h, string.h, stdio.h and Servo.h - for some reason Instructables drops them when I paste my code.
#include
#include
#include
#include
Servo myservo; // create servo object to control trigger servo
int pos = 90; // variable to store the trigger servo position
uint8_t outbuf[6];
int cnt = 0;
int ledPin = 13;
int servoPin = 7;
int servoPin2 = 6;
int pulseWidth = 0;
int pulseWidth2 = 0;
long lastPulse = 0;
long lastPulse2 = 0;
int z_button = 0;
int c_button = 0;
int refreshTime = 70; //tweaked for FutabaS3003 servos
int minPulse = 600; //tweaked for FutabaS3003 servos
int minPulse2 = 600; //tweaked for FutabaS3003 servos
int maxPulse = 2400; // maximum servo position
int maxPuls2e = 2400; // maximum servo position
int dtime=10;
#define pwbuffsize 10
long pwbuff[pwbuffsize];
long pwbuffpos = 0;
long pwbuff2[pwbuffsize];
long pwbuffpos2 = 0;
void setup()
{
myservo.attach(8); // attaches the trigger servo on pin 8 to the servo object
Serial.begin (9600);
Wire.begin ();
nunchuck_init ();
pinMode(servoPin, OUTPUT);
pinMode(servoPin2, OUTPUT);
pulseWidth = minPulse;
pulseWidth2 = minPulse2;
Serial.print ("Finished setup\n");
}
void nunchuck_init()
{
Wire.beginTransmission (0x52);
Wire.send (0x40);
Wire.send (0x00);
Wire.endTransmission ();
}
void send_zero()
{
Wire.beginTransmission (0x52);
Wire.send (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.receive ());
digitalWrite (ledPin, HIGH);
cnt++;
}
if (cnt >= 5) {
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:
muovi( outbuf[3] ,outbuf[2] );
break;
case 0:
muovi( outbuf[1]/2+0x3E ,outbuf[0]/2+0x3E );
break;
}
switch (z_button) {
case 0:
for(pos = 90; pos >= 120; pos += 1) // fires trigger when Z button pressed
{
myservo.write(pos);
delay(15);
}
for(pos = 120; pos >= 90; pos -= 2) // returns trigger to center
{
myservo.write(pos);
delay(15);
}
break;
case 1:
break;
}
}
cnt = 0;
send_zero();
}
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];
int accel_y_axis = outbuf[3];
int accel_z_axis = outbuf[4];
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 ("\r\n");
i++;
}
char nunchuk_decode_byte (char x)
{
x = (x ^ 0x17) + 0x17;
return x;
}
void muovi ( uint8_t x, uint8_t y){
float tilt = (700 - x*2*2);
float tilt2 = (0x7E - y + 0x7E) *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 pulseWidth += pwbuff[p];
pulseWidth2 += pwbuff2[p];
}
pulseWidth /= pwbuffsize;
pulseWidth2 /= pwbuffsize;
}
