Arduino Code

/*
 * Servo with Potentiometer control
 * Theory and Practice of Tangible User Interfaces
 * October 11 2007
 *
 * Code copied and doubled for use with two servos
 * by Andrew McDiarmid and Jess Kline
 * October 17 2007
 */

int servoPin = 7;      // Control pin for servo motor
int potPin   = 0;      // select the input pin for the potentiometer
int secondPotPin = 1;
int secondServoPin = 8;

int pulseWidth = 0;    // Amount to pulse the servo
int secondPulseWidth = 0;
long lastPulse = 0;    // the time in millisecs of the last pulse
long secondLastPulse = 0;
int refreshTime = 20;  // the time in millisecs needed in between pulses

int val;               // variable used to store data from potentiometer
int secondVal;

int minPulse = 500;   // minimum pulse width

void setup() {
  pinMode(servoPin, OUTPUT);  // Set servo pin as an output pin
  pinMode(secondServoPin, OUTPUT);
  pulseWidth = minPulse;      // Set the motor position to the minimum
  Serial.begin(9600);         // connect to the serial port
  Serial.println("servo_serial_better ready");
}

void loop() {
  val = analogRead(potPin);    // read the value from the sensor, between 0 - 1024
  secondVal = analogRead(secondPotPin);
 
  if (val > 0 && val <= 999 ) {
    pulseWidth = val*2 + minPulse;  // convert angle to microseconds
 
    Serial.print("moving servo to");
    Serial.println(secondPulseWidth,DEC);
  }
 
  if (secondVal > 0 && secondVal <= 999) {
    secondPulseWidth = secondVal * 2 + minPulse; 
    Serial.print("moving second servo to ");
    Serial.println(secondPulseWidth,DEC);
  }
 
  updateServo();   // update servo position
  secondUpdateServo();
}

// called every loop().
void updateServo() {
  // pulse the servo again if rhe refresh time (20 ms) have passed:
  if (millis() - lastPulse >= refreshTime) {
    digitalWrite(servoPin, HIGH);   // Turn the motor on
    delayMicroseconds(pulseWidth);  // Length of the pulse sets the motor position
    digitalWrite(servoPin, LOW);    // Turn the motor off
    lastPulse = millis();           // save the time of the last pulse
  }
}

void secondUpdateServo() {
  // pulse the servo again if rhe refresh time (20 ms) have passed:
  if (millis() - secondLastPulse >= refreshTime) {
    digitalWrite(secondServoPin, HIGH);   // Turn the motor on
    delayMicroseconds(secondPulseWidth);  // Length of the pulse sets the motor position
    digitalWrite(secondServoPin, LOW);    // Turn the motor off
    secondLastPulse = millis();           // save the time of the last pulse
  }
}

Photos

 Flickr links coming courtesy of k7...