After creating a more fully-outfitted workbench, I dove into a capacitive sensing noise maker, commonly known as a Theremin.
Although, to be accurate, this is not a theremin in the truest sense. It beeps and makes a variety of ascending and descending tones in response to hand movement, but it doesn’t make the classic theremin sound.
This project was pretty tricky at first. Keeping the soldering clean makes a big difference in a circuit like this because any additional mass can change the properties of the circuit in drastic ways.
Likewise, the value of the inductor made a huge difference. I only had one with the correct value, and it broke. That left me trying to make something work with other values with less success.