Description
I used some balsa wood, styrofoam packing peanuts, and tape for my crawler. The servo motor is oriented upside-down and balsa wood legs are taped to the head. I glued packing peanuts together to make the legs, and taped a glued group of peanuts to the front of the motor for stability. I also put a piece of tape at the bottom of the stabilizer to reduce traction. Finally, I wrote a program that automatically actuates the crawler. It uses the servo_serial code and alternates between the '5' and '8' settings every 750 milliseconds.
I've noticed the crawler is more successful on some surfaces than another, and it's a little bit brittle. However, given a rough enough surface, it seems to crawl forward reasonably. A video is here: http://www.youtube.com/watch?v=1uIZWeYJ11I.
Materials
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Servo motor
-
Arduino
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8 Styrofoam packing peanuts
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Balsa wood
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Masking tape
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Hot glue
Code
/*
* Servo Control Serial
* modified for TUI October 2011
* Servo Serial Better
*
* Nicholas Kong
* October 16, 2011
*
* -------------------
*
* 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
long switchPulse = 0;
int refreshTime = 20; // the time in millisecs needed in between pulses
int switchTime = 750;
int val; // variable used to store data from serial port
int minPulse = 500; // minimum pulse width
int maxPulse = 2250; // maximum pulse width
boolean on = false;
boolean six = true;
void setup() {
pinMode(servoPin, OUTPUT); // Set servo pin as an output pin
pulseWidth = (5*(maxPulse-minPulse) / 8) + minPulse;
Serial.begin(9600); // connect to the serial port
}
void loop() {
//val = six ? '1' : '9';
val = Serial.read(); // read the serial port
if (val == '1') {
on = true;
} else if(val == '0'){
on = false;
}
if(on)
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) {
pulseWidth = ((six ? 5 : 8) * (maxPulse-minPulse) / 8) + minPulse;
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
}
if(millis() - switchPulse >= switchTime) {
six = !six;
switchPulse = millis();
}
}
