Hi all, I am new here and learning the Arduino platform. I have built my first robot, a light follower, and loaded the following code from http://www.instructables.com/id/The-Arduino-Mothbot/step11/Completing-the-Arduino-Mothbot/ .
* Arduino Mothbot
*
* Digital Pin Wiring:
* pin 7 - Pushbutton Signal
* pin 11 - Right Servo Signal
* pin 3 - Left Servo Signal
*
* Analog Pin Wiring:
* pin 0 - Left Light Sensor Signal
* pin 1 - Right Light Sensor Signal
*
* License: This work is licenced under the Creative Commons
* Attribution-Share Alike 3.0 Unported License. To
* view a copy of this licence, visit
* http://creativecommons.org/licenses/by-sa/3.0/
* or send a letter to Creative Commons, 171 Second
* Street, Suite 300, San Francisco, California 94105,
* USA.
*/
//------------------------------------------------------------------------
// START OF ARDUINO MOTHBOT SETUP
//--- Library
#include <Servo.h>
//--- Pin Definitions
#define LEFTSERVOPIN 3 //The digital pin that the left servo is connected to
#define RIGHTSERVOPIN 11 //The digital pin that the right servo is connected to
#define LEFTLIGHTSENSOR 0 //The analog pin the left light sensor is connected to
#define RIGHTLIGHTSENSOR 1 //The analog pin the right light sensor is connected to
#define PUSHBUTTON 7 //The digital pin that the pushbutton sensor is connected to
#define LED 13 //The LED on the arduino
//--- Servo Setup
Servo leftServo;
Servo rightServo;
//--- Speed Setup
int robotSpeed = 75; //set the speed of the robot
int rightSpeed = 50;
int leftSpeed = 50;
//--- Sensor Values
int leftLightSensorVal = 0;
int rightLightSensorVal = 0;
int lightSensorThreshold = 200;
//--- On/Off values
int pushButtonVal = 0;
int old_pushButtonVal = 0;
int pushButtonState = 0;
//--- Delay Threshold
int delayParam = 10; //Supported Times - 0 - 255 (0 to 25.5 Seconds) value * 100 milliseconds
// END OF ARDUINO MOTHBOT SETUP
//------------------------------------------------------------------------
//------------------------------------------------------------------------
//START OF ARDUINO MOTHBOT PROGRAM
//--- The program setup
void setup()
{
Serial.begin(9600); //Starts the serial port
robotSetup(); //sets the state of all neccesary
//pins and adds servos to your sketch
}
//--- The main program code
void loop()
{
//--- Get information from the light sensor
leftLightSensorVal = analogRead(LEFTLIGHTSENSOR);
rightLightSensorVal = analogRead(RIGHTLIGHTSENSOR);
//--- Get information from the pushbutton sensor
pushButtonVal = digitalRead(PUSHBUTTON);
//--- Set the state of the pushbutton
if((pushButtonVal == HIGH) && (old_pushButtonVal == LOW))
{
Serial.println("Button Pushed");
pushButtonState = 1 - pushButtonState;
delay(10); // Simple de-bouncing
}
//--- Reset the state of the push button
old_pushButtonVal = pushButtonVal;
//--- If pushbutton state HIGH then turn on the robot and
// listen to the light sensor information
if(pushButtonState == 1)
{
digitalWrite(LED, HIGH); // turn LED ON
if(leftLightSensorVal - rightLightSensorVal >= lightSensorThreshold)
{
Serial.println("Left");
goLeft();
delay(delayParam * 100);
goStop();
}
else if(rightLightSensorVal - leftLightSensorVal >= lightSensorThreshold)
{
Serial.println("Right");
goRight();
delay(delayParam * 100);
goStop();
}
else
{
Serial.println("Forward");
goForward();
delay(delayParam * 100);
goStop();
}
}
else
{
Serial.println("Stop");
digitalWrite(LED, LOW); // turn LED OFF
goStop();
}
}
//END OF ARDUINO MOTHBOT PROGRAM
//------------------------------------------------------------------------
//------------------------------------------------------------------------
//START OF ARDUINO MOTHBOT FUNCTIONS
//--- The setup for the robot
void robotSetup()
{
//--- Set the speed of the robot
setSpeed(robotSpeed);
//--- Set up the servos
pinMode(LEFTSERVOPIN, OUTPUT); //sets the left servo signal pin
//to output
pinMode(RIGHTSERVOPIN, OUTPUT); //sets the right servo signal pin
//to output
leftServo.attach(LEFTSERVOPIN); //attaches left servo
rightServo.attach(RIGHTSERVOPIN); //attaches right servo
//--- Set up the pushbutton
pinMode(PUSHBUTTON, INPUT); //sets the pushbutton sensor pin to input
//--- Set up the LED to see robot state
pinMode(LED, OUTPUT); //sets the led pin as output
//--- Tell the robot to stop the servos
goStop();
}
//--- Set the speed of the robot between 0-(stopped) and 100-(full speed)
void setSpeed(int newSpeed)
{
setSpeedLeft(newSpeed); //sets left speed
setSpeedRight(newSpeed); //sets right speed
}
//--- Set the speed of the left wheel
void setSpeedLeft(int newSpeed)
{
if(newSpeed >= 100) {newSpeed = 100;} //if speed is greater than 100
//make it 100
if(newSpeed <= 0) {newSpeed = 0;} //if speed is less than 0 make
//it 0
leftSpeed = newSpeed * 0.9; //between 0 and 90
}
//--- Set the speed of the right wheel
void setSpeedRight(int newSpeed)
{
if(newSpeed >= 100) {newSpeed = 100;} //if speed is greater than 100
//make it 100
if(newSpeed <= 0) {newSpeed = 0;} //if speed is less than 0 make
//it 0
rightSpeed = newSpeed * 0.9; //scales the speed to be
}
//--- Move the robot forward
void goForward()
{
leftServo.write(90 + leftSpeed);
rightServo.write(90 - rightSpeed);
}
//--- Move the robot backward
void goBackward()
{
leftServo.write(90 - leftSpeed);
rightServo.write(90 + rightSpeed);
}
//--- Move the robot right
void goRight()
{
leftServo.write(90 + leftSpeed);
rightServo.write(90 + rightSpeed);
}
//--- Move the robot left
void goLeft()
{
leftServo.write(90 - leftSpeed);
rightServo.write(90 - rightSpeed);
}
//--- Stop the robot
void goStop()
{
leftServo.write(90);
rightServo.write(90);
}
//END OF ARDUINO MOTHBOT FUNCTIONS
//------------------------------------------------------------------------
It does work, however the motion is not smooth. Instead of following the light, it just turns toward the light. For example, when light is sensed on one side or the other, the robot, moving forward, then turns about 90 degrees in the direction of the light and then moves forward once again. From what I can tell, the sketch is controlling the motors as intended. I would like to improve on the design slightly and make the robot actually follow the light as the light moves.
I would like to achieve something like this:
Can anyone offer any suggested modifications to the code that would help me achieve this? Alternatively, is this expected performance based on the code above? Maybe I have done something wrong...its possible 