/*
 Random DC Motor Motion
 by Carlyn Maw 
 
 This program moves a DC motor a random amount in one direction, then a different 
 amount in the opposite direction, indefinitely. Speed of the motor is increased
 with the size of the random number.
 

 Created 22 February 2010
 Updated 

 */

  const int motorPin1 = 7;    // H-bridge leg 1 (pin 2, 1A)
  const int motorPin2 = 6;    // H-bridge leg 2 (pin 7, 2A)
  const int motorPulsePin = 11;    // H-bridge enable pin
  
  const int myMotorPWMin = 220;  // min PWM value based on your motor and power supply
  const int myMotorPWMax = 255; // max PWM value based on your motor and power supply
  
  const int myMotorCyclesMin = 6000;  // min number of program cycles for motor to be on
  const int myMotorCyclesMax = 25000; // max number of program cycles for motor to be on
  const int driftFactor = 800;  // compensates for systems tendency to drift left
  

int motorCycles; //amount of time motor will move in any direction
long rNum;      // random muber that will be the number of steps the motor will move
int mySpeed =250;            // the delay interval between steps. The smaller the faster. 



//  function prototypes:
void blink(int howManyTimes);


void setup() {

  //Set pin modes 
   pinMode(motorPin1, OUTPUT); 
    pinMode(motorPin2, OUTPUT); 
    pinMode(motorPulsePin, OUTPUT);

  
  // start  program with a half-second delay:
  delay(500);  

  // blink the reset LED 3 times:
  blink(3);
  
  //seed random from analog pin so pattern is different everytime
  randomSeed(analogRead(0));

}

void loop() {

  rNum = random(0,100);
  motorCycles = rNum*(myMotorCyclesMax-myMotorCyclesMin)/100 + myMotorCyclesMin;
  mySpeed = (100-rNum)*(myMotorPWMax-myMotorPWMin)/100 + myMotorPWMin;
  motorCycles = motorCycles + driftFactor; // this motor trends to the left, the driftFactor compensates
  
  for (int i = 1; i<= motorCycles; i++) {
      analogWrite(motorPulsePin, mySpeed);
      digitalWrite(motorPin1, LOW);   // set leg 1 of the H-bridge low
      digitalWrite(motorPin2, HIGH);  // set leg 2 of the H-bridge high

  }

  // move motor backward 
  rNum = random(0,100);  
  motorCycles = rNum*(myMotorCyclesMax-myMotorCyclesMin)/100 + myMotorCyclesMin;
  mySpeed = (100-rNum)*(myMotorPWMax-myMotorPWMin)/100 + myMotorPWMin;

  for (int i = 1; i<= motorCycles; i++) {
      analogWrite(motorPulsePin, mySpeed);
      digitalWrite(motorPin2, LOW);   // set leg 2 of the H-bridge low
      digitalWrite(motorPin1, HIGH);  // set leg 1 of the H-bridge high
  }
}



// Blink the reset LED:
void blink(int howManyTimes) {
  int i;
  for (i=0; i< howManyTimes; i++) {
    digitalWrite(13, HIGH);
    delay(200);
    digitalWrite(13, LOW);
    delay(200);  
  }
}