Genelec GLM IR remote volume control DIY prototype.

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Genelec GLM IR remote volume control DIY prototype.

connection:
L-out to 3.5mm tip, L-ground to 3.5mm ground.

potentiometer :
Alps 50K motorized.
 

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Hi!
This is a very useful idea. I measured the 9310A Volume Controller using a multimeter and it seems to contain a logarithmic 10k potentiometer.

I plan to use an Alps RK27 LOG 10k potentiometer (tested and works perfectly with the GLM calibration unit) and control it using a Raspberry Pi running a 28BYJ-48 5V stepper motor + ULN2003 driver.

There are instructions for setting up the motor here: Controlling Stepper Motors using Python with a Raspberry Pi

Tweaking that python software should be quite easy: just take an argument how many steps to increase or decrease the volume and then run that bit sequence in original or reversed order. The resolution (2048 full steps per revolution) is more than sufficient. Obviously keeping track of the set volume value would have to be done somehow (I plan to use node-persist for this). The major concern is whether the stepper motor's torque (~ 34 mNm) is enough to turn the potentiometer without stalling. The Alps potentiometer is rather stiff and I might have to look for some potentiometer with lower torque. The 9310A is extremely smooth, so that has something suitable inside, but I don't want to break that by opening it. :)
My ultimate goal is to control volume from Volumio music player. That should be possible by modifying the scripts used by this plugin: ALLO - Relay Attenuator * Volumio
Does this sound realistic? Ill post an update here if I actually get it working.
 
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