Episode 435: Raspberry Pi 4 Music Player w/ Analog Controls

Thank you!

Below is the best I have for a schematic. Unfortunately, it does not include the CAP1188 Capacitance sensor for the fader, but if I recall correctly I used SPI for that to connect to the Raspberry PI. Adafruit has great documentation for that device.

For the parts, if you look in the "Additional Parts" section above it describes the fader, and which type of pot I used for the volume. Those faders are sometimes difficult to find, but if you just google the description above you will get some hits. Just make sure you find one that is the right length for your project. They vary in size. The fader has contacts for a potentiometer just like you would expect, connections for the motor, and another lead for capacitance.

I am in the middle of a move, and that device is still packed up. But if you have troubles with that part I can try to find it and trace out the fader portion.

Here is the schematic that I was able to dig up.

Good Luck with your build!

-Kaleb Clark

Kaleb,

great project. I will build it for my 5year old daughter with a horse riding on the slider in front of a princess castle being the player. I am searching for a good idea for weeks now and yours is second to none.

I shall try to use a waveshare 7display and I further plan to use a simpler web ui rather than the official volumio.

Recourses zip seem to only have stl files in it. I cannot find wiring diagrams and a bit of explanation around the hardware, in particular what motor specs for the slider and why and what kind of volume poti rather than a rotary encoder?. Any chance to post wiring and some more info, as this would make a built much less try and error.

Cheers Andreas

Hi,

Nice project. I am trying to do it but stuck in connections, can you help me with the Schematics.

Oh that’s why I thought It was so great, I’ve had a little time in the studio myself    not a lot, think entourage and trumpet instead of front man or songwriter  

Hi, think the volume would work better with a log pot.

They sure are Travis. Check the zip file on this page. Should all be in there.

-Kaleb

Are the STL files available for the 3D printing the enclosure?

Andrew, that blew my mind. I am an audio engineer and own a few control surfaces with motorized faders that DO have conductive handles on them. But it *never* crossed my mind to just use one of those. I guess that is just how deep in DIY I was on this project!

I would still like to make one, but if that does not pan out, Ill probably go that route. Though in the ~week of using the device it really has not been an issue. I can still grab what is there and move it. Mostly aesthetic at this point.

Thanks for the great idea and jolt back into reality! haha

-Kaleb

What a fun project - great job. I was determined to rebuild a vintage radio and replace the tuner's linear needle with a similar motorized pot. Based on the research I did, it was the most reliable way to build an inexpensive and compact linear actuator for a short-travel lightweight load (needle) with builtin encoding. I didn't need the conductive feature for my project, but I did learn that such knobs are available for the intended application (audio mixing boards). You can buy these knobs (and sometimes the pots too) pulled from broken mixing boards. If you want to buy a new knob, Selco advertises them available in quantities as low as one. Their website indicates that conductive knobs are available, but does not indicate which part numbers have that feature. https://www.selcoproducts.com/knobs/slider-knobs

I've also used Volumio in projects and love it. A feature I really longed for, and would like to have time to develop and share as a plugin someday, is integrated control for a I2C FM Tuner module.

Thanks, Thomas, I got the idea for the dim functionality from studio monitor control systems. Very handy when you need to talk to someone but not interrupt playback.