Assignment: Servo Motor: Actuation Assignment 2

Collaborators:

Assignment: Servo Motor: Actuation Assignment 2
Collaborators:

Author: Erin Knight

Description:

This week we progressed our actuation abilities with Servo motors!  Yay!  After setting up the circuitry, I tried controlling the Servo with a pot as well as serial input.

Then I set off on a mission to create my own crawling bot.

It was hard.

I first attempted to make a tricycle with the servo as the front wheel but because the servo only goes 180degrees, I could only make the tricycle go a litte ways forward and then backwards.

Back to the drawing board...

After different interations and several pin pricks and super glue disasters, I ended up with Mr. Fork Cork Crab.  He scoots along slowly, staring at you with his beady yellow eyes the entire time. *shiver*

Pictures and Video:

Here are some pics of Mr. Cork Fork Crab.

He wasn't moving as well as I wanted so his feet got casts and bling (with clips!)

The video's are attached at the bottom, for some reason Flickr isn't playing nice with my videos so couldn't imbed them.  Sorry for the lighting.

Code:

/*
* 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
}
}