/*________________________________________
 *     U C I   S T U D Y   G R O U P
 *          Lesson 2: MOSFETS
 *             Ron Kessler
 *          Created 5/7/2021
 * 
 * RAMPUP & DOWN DEMO
 * _______________________________________
 * This shows how to slowly increase motor RPM to maximum and
 * then slowly reduce RPM to 0. This runs for ever. 
 * 
 * Be sure to connect a 10K resistor (brn-blk-orange) between the
 * Gate and Source (ground on the Arduino). This pulls the Gate to gnd
 * should the yellow wire (Gate) get pulled loose.
 * 
 * When you hold the transistor so you can view the label, the pins are
 * from left to right: Gate | Drain | Source
 * 
 * Wiring: 
 *   IRF540           Arduino                  Motor
 * Gate Yellow        Pin 11
 * Source Green       GND 
 *                    VIN (on Arduino)        Motor (+)
 * Drain Orange                               Motor (-)
 * 
 * 
 */

//---define our controller pin
const int motorPin = 11;

void setup() 
{
  pinMode(motorPin, OUTPUT);    //we are sending power out

}

//---ramp the motor RPM up to max then back to 0
//---Our range of values is 0-255 because we are using 1 byte of data
void loop() 
{
  for(int x = 0; x< 255; x++)     //increase motor speed from 0-255
  {
    analogWrite(motorPin, x);
    delay(20);
  }

  for(int x = 255; x > 0; x--)    //decrease motor speed fro 255-0
  {
    analogWrite(motorPin, x);
    delay(20);
  }

}