[SOLVED] Rotary encoder library for Keyes KY-040

void loop() {
if (old_count != count) {
Serial.print(millis());
Serial.print(" ");
Serial.println(count);
old_count = count;
}
}

You can find more illustrations here http://olliesworkshops.blogspot.com/201 … witch.html

You can measure it with an oscilloscope or a logic analyzer. Please take a look of the logi analyzer screenshots on my blog post where there observations are demonstrated.

[Ollie – Wed May 30, 2018 4:37 pm] –
The interrupt method doesn’t work with the mechanical encoders due to noise and cross-talk. An RC filter could be used to address that, but it can be difficult to find a balance between filtering and missing high speed real pulses. My own conclusion is that only a software filter with polling works. In a F103C8, my application is polling at 10 kHZ speed without causing any noticeable CPU load.

You can find more illustrations here http://olliesworkshops.blogspot.com/201 … witch.html

I have never had a skipped reading with that code and a KY-040, I did put a couple of low value tantalum capacitors as insurance.

Here is an example how the polling and decision on the change was made (ENA and ENB are the inputs):
encstat = rl (encstat); // shift encstat two bits left to get previous...
encstat = rl (encstat); // ...encoder sample in bits 3..2
encstat &= 0b00001100; // strip garbage other than bits 3..2

if (ENC_TYPE_QD)
{
switch (encstat){
case 0b0000: goto enc_done; // 00 -> 00 = no change
case 0b0001: goto enc_inc; // 00 -> 01 = increment
case 0b0010: goto enc_dec; // 00 -> 10 = decrement
case 0b0011: goto enc_done; // 00 -> 11 = illegal, ignore
case 0b0100: goto enc_dec; // 01 -> 00 = decrement
case 0b0101: goto enc_done; // 01 -> 01 = no change
case 0b0110: goto enc_done; // 01 -> 10 = illegal, ignore
case 0b0111: goto enc_inc; // 01 -> 11 = increment
case 0b1000: goto enc_inc; // 10 -> 00 = increment
case 0b1001: goto enc_done; // 10 -> 01 = illegal, ignore
case 0b1010: goto enc_done; // 10 -> 10 = no change
case 0b1011: goto enc_dec; // 10 -> 11 = decrement
case 0b1100: goto enc_done; // 11 -> 00 = illegal, ignore
case 0b1101: goto enc_dec; // 11 -> 01 = decrement
case 0b1110: goto enc_inc; // 11 -> 10 = increment
case 0b1111: goto enc_done; // 11 -> 11 = no change
}
}


[madias – Wed May 30, 2018 3:59 pm] –
You can try out my code I’ve written some years ago
viewtopic.php?f=18&t=15&p=21

Thanks Madias, I’ve already seen your post and tried it but couldn’t get it to work. But that is probably due to my lack of coding skills.

[Manny – Wed May 30, 2018 4:15 pm] –
enum { PinA=PB4, PinB=PB5, IPINMODE=INPUT_PULLUP };

......

old_count = count;
}

}