Pasted

/*
This is used for testing AF coil by sweeping PWM values and thereby changing duty cycle of the PWM output.
The PWM frequency on most pins is ~490 Hz. However, it's ~980 Hz for pins 5 and 6 on the Uno, and for pins 3 and 11 on the Leonardo
 
Ayush Sagar
15 Jul 2014
*/
 
int coilPin = 11;   
int value = 0;   
int increment = 1;
 
void setup() {
  // Set coil pin to output
  pinMode(coilPin, OUTPUT);
}
 
// the loop routine runs over and over again forever:
void loop() {
  // value reset condition
  if (255 - value < 1) value = 0;
  
  // set PWM:
  analogWrite(coilPin, value);
 
  // increment value
  value += increment;
  
  // delay
  delay(39);
}