Arduino Encoder Rotatorio LPD3806 - 600BM

Question

I have a project for the college where I have to perform a measuring wheel. In this case I used a rotatory Ncoder to perform the measurements, but I’m having problems at the time of the code. In case, at the moment I do not know how to program a rotating meeting, I am doing a search to find more information. The code I have is:

volatile unsigned int temp, counter = 0;

void setup() 
{
    Serial.begin(9600);
    pinMode(2, INPUT_PULLUP);
    pinMode(3, INPUT_PULLUP);
    attachInterrupt(0, ai0, RISING); 
    attachInterrupt(1, ai1, RISING);
}

void loop() 
{
    if (counter != temp) 
    { 
        Serial.println(counter);
        temp = counter; 
    }
}

void ai0() 
{ 
    if (digitalRead(3) == LOW)
        counter++;
    else 
        counter--;
}

void ai1() 
{
    if (digitalRead(2) == LOW) 
        counter--;
    else 
        counter++;
}

PROBLEM: In the code when I turn the wheel to the counter decrease (-1) and it is in the 0 position it jumps to +65874 in the positive value, it would need that when it was in the 0 position and rotated to decrease (-1) He wouldn’t leave 0, because the wheel won’t count a negative value. In the project I am using an LCD for the positions.

Answer 1

Before making a decrease couter--, make a check if the counter is different from zero. For example:

void ai0() 
{ 
    if(digitalRead(3)==LOW) 
        counter++;
    else if (counter != 0)
        counter--;
    }
}