# Let’s crawl

Description

It was hard to derive linear motion out of a motor whose direction of rotation alternates. Initially I tried to design shoes out of erasers but it turns out the friction was too much for it to begin moving. The video for this attempt can be found here – https://goo.gl/photos/QXmh7DSLDyzkFmXM8

To fix this problem, I tried removing the feet and reworked the placement of wires. I got something which moves a little but only on a rough surface like that of a carpet or a rug – https://goo.gl/photos/5Jiy4hLLPD3BEsbm6

Components

Arduino Board
``` /* * 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 = 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 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 <= 999 ) { pulseWidth = val*2 + minPulse; // convert angle to microseconds Serial.print("moving servo to "); Serial.println(pulseWidth,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 } } ```