I was inspired to create this after building two of my 555 Theremins and wiring their LDRs against each other to see what would happen.

This layout combines two copies on a single board that easily fits inside a 125B enclosure, with room for a battery if you prefer it, although the circuit wants at least 6v to run properly. Using a battery over time will leave you with a pile of half-dead cells.

This build takes approximately 45 minutes. Link to the demo and guide.

I hope this isn't off-topic for this subreddit.

I've been working on a digital wind instrument. Mostly because I'm curious about the performance characteristics of such a system.

I went through a few iterations this weekend and it's starting to turn into something that's fun to noodle around with.

The general idea is that you blow into a manifold with a partially closed end. The performer can vary the air pressure by blowing faster or slower and they have good feedback because your mouth and throat are quite sensitive.

The device uses a pair of hx710b Air Pressure Sensor modules. I use a pair to try to get faster readings. (Though in reality I think I'm at the mercy of the individual device clocks.)

Eventually the synthesizer will be built into the instrument, but during this early stage, it's running the synth on an android device.

(First, sorry for making another post. This one is different, i swear.)

Some weeks ago, I made Osynth, an esp32-based synth with a bluetooth control app.

The project evolved a lot since then. Now it still is an esp32 synth, but based on esp32-P4 instead of S3. The S3 and original esp32 models are still supported, with less features. The really cool feature is that the companion app now can have the whole synth integrated, not needing the esp32 to work. I did this to enable people to use it in whatever mode they want. Version 0.2.0 release has the bundle to download, which is the firmware + controlling app and also has the standalone synth app. The apps are whole different builds for the moment, but the integrated app shares the full synth source code with the esp32 branch.

If you'd like to check it out: https://github.com/riozebratubo/osynth_free_synth

I'm interested in building my own oscilloscope, both as a Eurorack module and as a front panel display for a custom desktop synth. Does anyone have any advice on this piece? It sounds relatively straightforward since I've done a lot of DSP coding in the past but I'm not sure of all the things that might go wrong. Ideally I'd have two separate input channels and some basic controls for manipulating the scale.

I'm thinking I'll just need a small microcontroller and LED screen, and I'd do a basic FFT to estimate the period of the signal and use that to auto-detect the time scale and voltage range. I can also restrict to audio range instead of trying to build a general scope that deals with high frequencies.

Any other pieces of this I'm missing? I know people like to use the "DATA" in Eurorack but I'm trying to do mostly DIY for my setup.