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Topic: Rotary Encoder, A different approach using one analog Pin (Read 1 time) previous topic - next topic


Jul 14, 2013, 05:11 pm Last Edit: Jul 16, 2013, 11:14 pm by billmax3 Reason: 1
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()
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;
   else {
 else if (hasTurned==true){
   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++


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.



Here is a picture


Neat! You made a 2-bit digital-to-analog converter.


Neat! You made a 2-bit digital-to-analog converter comparator..
Two analog values 3V or zero.. assuming a 20K pull-up resistor.

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