Assignment: Servo Motor: Actuation Assignment 2
Collaborators:

Assignment: Servo Motor: Actuation Assignment 2
Collaborators:

Assignment: To make a creepie-crawlie thing using a servo. I only had one servo, so my options were slightly limited. I tried a few different combinations of household objects, but had difficulty getting it to move forward until this final version. I call my final creation "Servo Man!". It moves forward - for a few steps - and then falls over. I didn't modify the servo program that was provided for the homework - my Servo Man walks forward while I alternately pushed 4 and 6 on the keyboard.

 

Materials:

arduino/breadboard/resistors/wires

1 servo

cardboard

cellophane tape

hot glue

wire from a wire hanger

 

Photos:

 

Video Link:

http://video.google.com/videoplay?docid=-3156213854951618868&hl=en

 

Code:

/*
 * 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 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
 Serial.println("Servo control program ready");
}

void loop() {
 val = Serial.read();      // read the serial port
 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);
 }
 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
 }
}