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Arduino reading double-din radio volume rotary dial knob

StealthRT

Sep 4, 2010
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Sep 4, 2010
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Hey all I bought a Chinese double din radio in order to modify it to my liking. The main reason why i went with this one is that it had a few buttons and turn knobs on the front and i wanted to use an Arduino in order to "read" this inputs in order to do stuff within my software program.

However, I am not quite sure what I need to check in order to find out how to go about hooking up the rotary dial knob buttons to the arduino so that i can read each "click" that it makes. They also have a push button mode when you press on the front of the rotary dial.

As a side note I will be supplying the power to these so nothing on the board will be used except the physical rotary dial - aside from a few resisters it seems as well.

Here are a few images of the pcb layout:

OSERU.jpg

veEWM.jpg

XvPVm.jpg


And knowledge would be great as to how to go about hooking this up to read by the arduino :)
 

kellys_eye

Jun 25, 2010
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There are three connections on one side of the control, two on the other.

The 'two' will be the push-to-make contacts of the rotary 'push' function. One side may be grounded and the other floating at +5V (grounded when the button is pushed).

The 'three' connections will be +5V, 0V and the encoder output (pulses). Although they are marked, I wouldn't trust them and a simple meter test for the +5V (might be 3.3V) supply will clarify matters.
 

StealthRT

Sep 4, 2010
146
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Alright another question - since this is an infinite turn in either direction how would i determine, say for music volume, if its back at 0 or if its all the way up?
 

AnalogKid

Jun 10, 2015
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The 'three' connections will be +5V, 0V and the encoder output (pulses).
Disagree.

A rotary encoder is not an active coomponent, and does not have 5 V and GND pins. It is two concentric rotary switch patterns. The three contacts are common, phase A, and phase B. The A and B patterns are 90 degrees out of phase.

A common interface is to connect the common pin to GND, connect each phase pin to a positive voltage through a resistor, and take the two outputs from the phase pins like open collector outputs with pull up resistors.

https://www.alps.com/prod/info/E/HTML/Encoder/Incremental/EC11/EC11E09244AQ.html

ak
EC11B15243AY_spec.jpg
 

kellys_eye

Jun 25, 2010
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6,514
Quite right. I was thinking of a different type of encoder :oops:

I can't quite see the marking on the control but the tracks look to have the centre pin grounded and the A/B pulses on the two outer pins (pulled high by resistors).
 
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