Alternatives to delay for keeping pins high

Using Arduino Programming Questions
1

Hi guys,

I am building an audio volume controller which i have working but need a little help with alternatives for the delay function.

I need to turn 2 transistors on based on the direction of a rotary encoder, if turned clockwise it will turn one transistor on for a tenth of a second and if its turned anticlockwise it will turn the other transistor on for a tenth of a second too.

The only problem is that while the delay is happening it doesn't read the encoder so it sort of pauses the reading for a little while.

I have tried to use the blink without delay example but cant figure out how to just keep the pin high for 100 milliseconds, it seams the blink without delay sketch uses some kind of switching technique to blink the led, is that right?

I think the solution lies with the mills() function but how would I implement that? (code below)

Thanks :slight_smile:

//these pins can not be changed 2/3 are special pins
int encoderPin1 = 2;
int encoderPin2 = 3;

int volUp = 13;
int volDown = 12;

volatile int lastEncoded = 0;
volatile long encoderValue = 0;

long lastencoderValue = 0;

int lastMSB = 0;
int lastLSB = 0;

void setup() {
  Serial.begin (9600);

  pinMode(encoderPin1, INPUT); 
  pinMode(encoderPin2, INPUT);

  pinMode(volUp, OUTPUT);
  pinMode(volDown, OUTPUT);

  digitalWrite(encoderPin1, HIGH); //turn pullup resistor on
  digitalWrite(encoderPin2, HIGH); //turn pullup resistor on

  //call updateEncoder() when any high/low changed seen
  //on interrupt 0 (pin 2), or interrupt 1 (pin 3) 
  attachInterrupt(0, updateEncoder, CHANGE); 
  attachInterrupt(1, updateEncoder, CHANGE);

}

void loop(){ 
  //Do stuff here
  
  

   if (encoderValue > 1)
{
    digitalWrite(volUp, HIGH); // turns on transister 1 to mkae volume go up
    delay(100);                // waits for a tenth of a second which simulates a quick button press
    digitalWrite(volUp, LOW);  // turns off the transister
    encoderValue = 0;          // resets position value to zero
    
    Serial.print("volume up");
}


  else if (encoderValue < -1)
{
    digitalWrite(volDown, HIGH); // turns on transister 1 to mkae volume go up
    delay(100);                  // waits for a tenth of a second which simulates a quick button press
    digitalWrite(volDown, LOW);  // turns off the transister
    encoderValue = 0;            // resets position value to zero
    
    Serial.print("volume down");
}





  Serial.println(encoderValue);
  delay(100); //just here to slow down the output, and show it will work  even during a delay
  

}


void updateEncoder(){
  int MSB = digitalRead(encoderPin1); //MSB = most significant bit
  int LSB = digitalRead(encoderPin2); //LSB = least significant bit

  int encoded = (MSB << 1) |LSB; //converting the 2 pin value to single number
  int sum  = (lastEncoded << 2) | encoded; //adding it to the previous encoded value

  if(sum == 0b1101 || sum == 0b0100 || sum == 0b0010 || sum == 0b1011) encoderValue ++;
  if(sum == 0b1110 || sum == 0b0111 || sum == 0b0001 || sum == 0b1000) encoderValue --;

  lastEncoded = encoded; //store this value for next time
}
2

Write down the EXACT steps YOU would perform if the job was to turn the pin on, and then, 100 hours later, turn the pin off.

You have a watch, a pad of paper, and a pencil. Nothing else.

The Arduino has a millis() function, some variables, and an assignment operator that correspond to the things you have.