My encoder is giving continuous value even the motor is idle

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1

I am using an optical encoder which came along with the stepper motor.

When i tried to read the pulse received from the encoder A+ and B+ with pin 2 and 3 in arduino uno i am receiving continuously increasing value or wrong count of rotation even it is idle.

Used Encoder is HN102-36A
HN102-36A-Rhett (rhett-hk.com)

Kindly help me to figure it out

2

Welcome to the forum

Please post your sketch, using code tags when you do

In my experience the easiest way to tidy up the code and add the code tags is as follows
Start by tidying up your code by using Tools/Auto Format in the IDE to make it easier to read. Then use Edit/Copy for Forum and paste what was copied in a new reply. Code tags will have been added to the code to make it easy to read in the forum thus making it easier to provide help.

3

Thanks for your reply. I had added the code i had used for testing the encoder input.

Kindly check this code

long count = 0;
unsigned long timep, time, etime;
bool A, B;
byte state, statep;

void AChange() {
  A = digitalRead(2);
  B = digitalRead(3);

  if (A == HIGH && B == HIGH) state = 1;
  if (A == HIGH && B == LOW) state = 2;
  if (A == LOW && B == LOW) state = 3;
  if (A == LOW && B == HIGH) state = 4;

  switch (state) {
    case 1:
      {
        if (statep == 2) count--;
        else if (statep == 4) count++;
        break;
      }
    case 2:
      {
        if (statep == 1) count--;
        else if (statep == 3) count++;
        break;
      }
    case 3:
      {
        if (statep == 4) count--;
        else if (statep == 2) count++;
        break;
      }
    case 4:
      {
        if (statep == 1) count--;
        else if (statep == 3) count++;
        break;
      }
  }
  statep = state;
}

void BChange() {
  A = digitalRead(2);
  B = digitalRead(3);

  if (A == HIGH && B == HIGH) state = 1;
  if (A == HIGH && B == LOW) state = 2;
  if (A == LOW && B == LOW) state = 3;
  if (A == LOW && B == HIGH) state = 4;

  switch (state) {
    case 1:
      {
        if (statep == 2) count--;
        else if (statep == 4) count++;
        break;
      }
    case 2:
      {
        if (statep == 1) count--;
        else if (statep == 3) count++;
        break;
      }
    case 3:
      {
        if (statep == 4) count--;
        else if (statep == 2) count++;
        break;
      }
    case 4:
      {
        if (statep == 1) count--;
        else if (statep == 3) count++;
        break;
      }
  }
  statep = state;
}

void setup() {
  Serial.begin(9600);
  pinMode(2, INPUT);
  pinMode(3, INPUT);

  attachInterrupt(digitalPinToInterrupt(2), AChange, CHANGE);
  attachInterrupt(digitalPinToInterrupt(3), BChange, CHANGE);

  timep = micros();

  A = digitalRead(2);
  B = digitalRead(3);

  if (A == HIGH && B == HIGH) statep = 1;
  if (A == HIGH && B == LOW) statep = 2;
  if (A == LOW && B == LOW) statep = 3;
  if (A == LOW && B == HIGH) statep = 4;
}

void loop() {
  time = micros();
  etime = time - timep;
  Serial.println(count);
  if (etime > 1000000) {
    Serial.println(count);
    timep = time;
  }
}
4

Try this.

  pinMode(2, INPUT_PULLUP);
  pinMode(3, INPUT_PULLUP);
5

Tried using INPUT_PULLUP the count value remains zero even i rotate the shaft

6

Then try reverting to just using input in the code, and add a pull down resistor of 10K to the Pins 2 & 3 of your Arduino.

7

If you use INPUT_PULLUP then, not surprisingly, the input will be normally HIGH

You need to arrange the circuit so that the input pin is taken LOW when the switch is activated and change the code so that the LOW input is detected rather than the HIGH input

8

Got a voltmeter? Check the voltages on pins 2 and 3 as you slowly rotate the encoder.

9

count need to be declared as volatile
You never reset count to 0

1 Like
10

Try the Encoder library from the IDE library manager. Load the "Basic" program from the "Examples" folder and turn the motor by hand to test your encoder.

11

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