Doubt with encoders

Hi people, I’m a bit confussed with encoders. I have EC11 encoders and the information that I found on the web shows that I should use some capacitors and resistors in some pins to connect this to an arduino…
But the weird thing was that before I read this I was trying differents connections without any resistor or capacitor (I have to say I’m very new in electronics), and the only connection that actually works was when I connect A and B to digital pins, C to ground, and in the other side (for the push button) one to digital pin and the other also to ground.
That works perfect, but is very different to the information that I found, so, I don’t know if this connection maybe could damage the arduino or maybe the encoder itself…
So I would like to know your opinion, because I don´t know just to leave this connection like that, or try the connection with the resistors and capacitors. Thanks!

Some use the resistor-capacitor system to debounce the encoder contacts in hardware so as not to use processor time running debounce code.  Others debounce in software so as to save on external components.  If it works and you’ve got INPUT_PULLUP enabled you should be good to go.

Wire all three encoder inputs as S3 is below

There are some tutorials on line for Arduino and the EC11, like this one.

You don’t need the resistors and capacitors if you debounce it using the Arduino.

Hang on. Encoders have multiple output signals and they are phased. So, one goes high then another goes high. If you read the inputs correctly (i.e. read one signal then another) then there is no need to de-bounce.
Plus this phased reading also allow you to determine the direction of the encoder.

Can you post a diagram of your circuit and links to circuits you have queries about?

Thanks… Tom… :grinning: :+1: :coffee: :australia:

Forget about caps and resistors, use the internal pull-ups, with the connections you have already given.
And forget about complicated debounce routines.

The “sliding noise” is given as 2-3 msec so for the encoder all you need is a simple “if its the same after 3 msec” line.

For the push switch you can use the same routing, but I’d suggest a longer period - say 20msec.


The datasheet gives it characteristics with 5K, this would be to ensure a “wetting current” to help with the sliding contacts.
The internal pullups are in the region of 10’s of KOhms.

Tom… :grinning: :+1: :coffee: :australia:

HI guys, Thank you very much for your answers… now I feel safe to keep the first connection I did.
Thank you all!

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