This 3-person collaborative instrument was inspired by OK Go music videos and Rube Goldberg machines. It consists of 4 different noisemakers: input from an FSR moves a mallet across a xylophone, input from a photocell moves another mallet to strike either a group of bells and a small cowbell, input from a photocell determines the direction in which a 360-degree servo motor turns a tower of spoons hitting jars and cans, and a soft circuit stuffed doll uses a photocell and translates the input with a piezo speaker. Code and materials for the soft circuit are available on this post.
Video of the spoons and jars can be found here.
Video of the bells (cowbell not attached) can be found here.
Components:
- Wooden board and assorted blocks
- Spoons, jars, cans, glass beads (for weight)
- Wooden mallets, xylophone
- Bells and string
- Small cowbell
- Tape, T-pins, zip strips, and other various fastening materials
- 1 soft circuit "Creepy Medusa" (see above for link to details)
- 2 servo motors
- 1 360-degree servo motor
- 1 FSR
- 2 photocells
- 4 Arduinos
- 4 breadboards
- 10k-ohm resistors for FSR and photocells
Code:
Photocell and FSR controlled:
/*
* Servo with Potentiometer control
* Theory and Practice of Tangible User Interfaces
* October 11 2007
*/
int servoPin = 7; // Control pin for servo motor
int potPin = 0; // select the input pin for the potentiometer
int pulseWidth = 10; // Amount to pulse the servo
long lastPulse = 0; // the time in millisecs of the last pulse
int refreshTime = 20; // the time in millisecs needed in between pulses
int val; // variable used to store data from potentiometer
int minPulse = 500; // minimum pulse width
void setup() {
pinMode(servoPin, OUTPUT); // Set servo pin as an output pin
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
if (val > 0 && val <= 2000 ) {
pulseWidth = val*3 + minPulse; // convert angle to microseconds
Serial.print("moving servo to ");
Serial.println(val,DEC);
}
updateServo(); // update servo position
}
// called every loop().
void updateServo() {
// pulse the servo again if the refresh time (20 ms) has 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
}
}
