Used mouse rotary encoder

Other Hardware General Electronics
1

Hi there !

I am currently doing experiments with a salvaged mouse rotary encoder.

the problem i’m facing isn’t from the code itself, ‘cos i tried a bunch of ‘em i’ve found on internet

the problem is, this encoder is quite old, it come from a mouse i’ve been using for a while now, so of course it is used, and the contacts A and B aren’t tight anymore.

here’s an example of code i used to make it work (not my code !) :

#define encoder0PinA 2
#define encoder0PinB 3
#define encoder0Btn 4
int encoder0Pos = 0;
void setup() {
  Serial.begin(9600);
  pinMode(encoder0PinA, INPUT_PULLUP);
  pinMode(encoder0PinB, INPUT_PULLUP);
  pinMode(encoder0Btn, INPUT_PULLUP);
  attachInterrupt(0, doEncoder, CHANGE);
}
int valRotary,lastValRotary;
void loop() {
  int btn = digitalRead(encoder0Btn);
  Serial.print(btn);
  Serial.print(" ");
  Serial.print(valRotary);
  if(valRotary>lastValRotary)
  {
	Serial.print("  CW");
  }
  if(valRotary  {

	Serial.print("  CCW");
  }
  lastValRotary = valRotary;
  Serial.println(" ");
  delay(250);
}
void doEncoder()
{
  if (digitalRead(encoder0PinA) == digitalRead(encoder0PinB))
  {
	encoder0Pos++;
  }
  else
  {
	encoder0Pos--;
  }
  valRotary = encoder0Pos/2.5;
}

and using it with a new rotary encoder (not from a mouse), it works very well.

But with the old mouse encoder here’s what happens (on the serial monitor) :

rotating in one way, i get “rotating clockwise”. Good, it works.

now the other way, i get “rotating counter-clockwise” then “clockwise” the “counter..” etc.

does anyone knows if i can compensate in a way or an other the fact the this component is used ? i already tried using a delay, it doesn’t change anything.

2

Hi, can you please post an oscillogram of the A and B waveforms, both rotating CW and CCW?

3

You could clean it with contact cleaner.
Also add few millisec debounce to your doEncoder.
And don't use decimal value to scale valRotary (which is int).

4

Hth:
https://community.element14.com/members-area/personalblogs/b/blog/posts/rotary-encoders---part-3-capturing-input-on-an-arduino

https://community.element14.com/members-area/personalblogs/b/blog/posts/rotary-encoders---part-1-electronics

5

hey ! i’ll do that as soon as i can

6

Couldn’t it be that int.0 is related to digital pin 2? Is your board an Uno?

7

The use of digitalPinToInterrupt() is recommend when using attachInterrupt().

8

yes it is.

btw here’s the real code i used to make my tests (even though the one i’ve shown in my first post is quite similar) :

int pinA = 6;
int pinB = 7;
int encoderPosCount= 0;
int pinAlast;
int aVal;
boolean bCW;

void setup{
  //SET pinA and pinB and input
  pinMode(pinA, INPUT_PULLUP);

  pinMode(pinB, INPUT_PULLUP);
  pinALast = digitalRead(pinA);
  Serial.begin(9600);
  Serial.println("BEGIN");
  Serial.println();
}

void loop()
{
  aVal= digitalRead(pinA);
  if(aVal |=pinAlast)
  {
    if(digitalRead(pinB) != aVal) //rotatingClockwise
    {
      encoderPosCount ++;
      bCW = true;
    }
    else
    {
      bCW = false
      encoderPosCount --;
    }
    if(bCW)
    {
      Serial.println("rotate clockwise");
    }
    else
    {
      Serial.println("rotate counter-clockwise");
    }
    Serial.print("encoder count: ");

    Serial.println(encodePosCount);
    Serial.println();
  }
  pinAlast = aVal;
}