Using old radio potentiometer for Raspberry setup

[thoughtfission]

@thoughtfission

Modifying the Web search phrase to something like "raspberry pi vintage radio" will turn up dozens of projects. [Alert: there is a hostile subset of Internet users who immediately throw shade at any project which doesn't religiously refurbish analog electronics to original condition, especially old radios for some reason. See, for example, past Hackaday comments. Do not engage with the trolls.]

I'll be interested to hear how your volume control works out. AFAIK the potentiometer is always "audio taper" as approximated in an electro-mechanical device. The result is a nonlinear resistance vs rotation curve which resembles a dogleg. See, for example, https://eepower.com/resistor-guide/resis...er-taper/#

Whether you take the offboard ADC approach like Adrian's or an onboard approach where the Pi has to do the conversion (this latter is not the choice I'd make), you'll end up with a similar nonlinear digital output. I'm thinking this should work well for your application but it's worth keeping in mind.

Also, the traditional potentiometer is an inherently noisy---aka "scratchy"---device and many become increasingly so over time. Contact cleaner spray may help alleviate this. {[All the usual precautions....I only melted some plastic parts with this stuff once and I'm sure the accumulated fumes did nothing bad to me over time ]

Maybe I'm just being my usual Chicken Little here. You might ask Adrian what his experience has been implementing his potentiometer code. Various digital filtering techniques are available if the binning technique it uses isn't adequate in your application.

Regards,
Kent

@TheOldPresbyope

Hi Kent,


Thanks for the advice. I'll definitely let you know how it goes. It might take a while as this will be a pretty steep learning curve fo me. I'm now starting to wonder if I should just try to find an analogue decoder that fits the knob I have on the radio. IT might be asier than dealing with the inevitable noise and degredation you mentioned. I see Adrian had the same issue.

Will let you know how it goes.

Will also open all of the windows if I do end up using contact cleaner  

Thanks,
Grant