Arduino Forum

Using Arduino => Sensors => Topic started by: billmax3 on Jul 14, 2013, 05:11 pm

Title: Rotary Encoder, A different approach using one analog Pin
Post by: billmax3 on Jul 14, 2013, 05:11 pm
I connected a rotary encoders grey code Com (center pin) to A0, grey code pin 1 to arduino GRD and a 64k resistor to encoders gray code pins 1 and 2.
then I enabled A0 internal pullup resistor and wrote a code to determine whether the encoder turned left or write and used timer one to check for input changes It seems to be working well
this is the code I used it requires timerone library http://playground.arduino.cc/code/timer1

#include <TimerOne.h>
boolean gotHigh=false; //Used to check if it went to High value
boolean gotLow=false; //Used to Check if it went to Low value
boolean valueHigh=false; //Used to check if the last value is high or low to determine the rotation
boolean hasTurned=false;

void setup()
{
Serial.begin(9600);
pinMode(A0, INPUT_PULLUP); //Set the internal pullup resistor
Timer1.initialize(1000);  //Set the interval of the checks
Timer1.attachInterrupt( timerIsr ); // attach the service routine here
}

void loop()
{
 // Your code here
 

}


void timerIsr(){
int sensorValue = analogRead(A0);    
 if (sensorValue<950){
   if (sensorValue>400){valueHigh=true;
     gotHigh=true;
   }
   else {
   valueHigh=false;
   gotLow=true;
   }
 hasTurned=true;  
 }
 else if (hasTurned==true){
 hasTurned=false;
   if ((valueHigh==true) && (gotLow==true)){
     Serial.println("Left"); //you code here for left turns eg. Myval--
   }
   else if (gotHigh==true){
     Serial.println("Right");//you code here for left turns eg. Myval++
   }
 gotHigh=false;
 gotLow=false;
 }
}
Title: Re: Rotary Encoder, A different approach using one analog Pin
Post by: mhzpower on Jul 15, 2013, 08:41 pm
Cool.  I'm playing with a pec11 right now.  I saw a youtube article about wiring it up with a debounce circuit and it was not working.  I'm using a 328 so my inputs are limited.  I will be watching your work here and trying something similar my self.

Cheers
Title: Re: Rotary Encoder, A different approach using one analog Pin
Post by: billmax3 on Jul 16, 2013, 11:17 pm
Here is a picture
https://docs.google.com/file/d/0B7psmNlbHxTGR2F1a3o1VW92RlE/edit?usp=sharing
Title: Re: Rotary Encoder, A different approach using one analog Pin
Post by: liuzengqiang on Jul 21, 2013, 04:16 am
Neat! You made a 2-bit digital-to-analog converter.
Title: Re: Rotary Encoder, A different approach using one analog Pin
Post by: Docedison on Jul 21, 2013, 04:45 am
Quote
Neat! You made a 2-bit digital-to-analog converter comparator..
Two analog values 3V or zero.. assuming a 20K pull-up resistor.

Doc