Lab07 - Crawler
Description
Using a servo motor to make a crawler.
Components Used
2 Paper tube
1 Servo Motor
Source code
/*
* Servo Motor Crawler
* Fan Wai Pio 18 October 2011
*
*
* Modified by
* Servo Control Serial
* modified for TUI October 2007
* Servo Serial Better
* -------------------
*
* Created 18 October 2006
* copyleft 2006 Tod E. Kurt <tod@todbot.com>
* http://todbot.com/
*
* adapted from "http://itp.nyu.edu/physcomp/Labs/Servo"
*/
int servoPin = 7; // Control pin for servo motor
int potPin = 0;
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 valPulse = 2;
int inc = 1;
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
Serial.println("Servo control program ready");
}
void loop() {
val = analogRead(potPin); // read the serial port
pulseWidth = (valPulse * (maxPulse-minPulse) / 8) + minPulse; // convert val to microseconds
Serial.print("Moving servo to position ");
Serial.println(pulseWidth,DEC);
if( valPulse > 1 && valPulse < 3)
valPulse += inc;
else
{
inc*=-1;
valPulse +=inc;
}
delay(val);
updateServo(); // update servo position
}
// called every loop().
// uses global variables servoPi, pulsewidth, lastPulse, & refreshTime
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
}
}
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