# Theory and Practice of Tangible User Interfaces

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November 24, 2007
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October 2, 2007
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# Lab 07: Crawler w/ single servo motor

Project Members:
Seung Wook Kim

[Description]

- A crawler with a single servo motor

- The boom pushes against the ground in one direction only.

[Components]

- Servo Motor

- Erector Kits

- Rubber Band

- Paper Tape

- Cardboard

[Arduino Code]

int servoPin = 7;      // Control pin for servo motor

int pulseWidth = 0;    // 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 serial port

int minPulse = 500;   // minimum pulse width
int maxPulse = 2250;  // maximum 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
}

void loop() {
if (val >= '1' && val <= '9' ) {
val = val - '0';        // convert val from character variable to number variable
val = val - 1;          // make val go from 0-8
pulseWidth = (val * (maxPulse-minPulse) / 8) + minPulse;  // convert val to microseconds
Serial.print("Moving servo to position ");
Serial.println(pulseWidth,DEC);
}
}

// called every loop().
// uses global variables servoPi, pulsewidth, lastPulse, & refreshTime