Read velocity with a potentiometer

Using Arduino Sensors
#1

I’ve been wondering as to how I could obtain the velocity of a potentiometers rotational speed. I thought it would be as simple as obtaining the potentiometers resistance followed by the time for an initial and a final values. But I’m not getting any change in speed when I adjust the pot.

Here’s my code:

  long t1 = 0;
  long t2 = 0;
  int v1 = 0;
  int v2, pot, cal, speed, start, potval;
 
void setup()
{
  Serial.begin(9600);
  pinMode(A0, INPUT);
}

void loop()
{
  potval = analogRead(A0);
  pot = map(potval, 0, 1023, 0, 200);
  if(t1 = 0){ 
    t1 = micros();
    v1 = pot;
    t2 = 0;
  }
  if(t2<t1){
    t2 = micros();
    v2 = pot;
  }
  cal = (v2-v1)/(t2-t1);
  speed = abs(cal);
  t1 = 0;
  v1 = 0;
  Serial.println(speed);
}
#2

I hope you realize that you are trying to measure angular velocity, not just plain velocity

1.) Use == instead of = in your first if statement

2.) Either make pot a float, or just use potval and not pot

3.) Use comments to make your logic easier to understand

4.) Double check your logic (remembering that you are measuring angular velocity)

#3

Remember, potentiometers may come in linear models or logarithmic models. You can get 10-turn models.

Paul

#4