For controlling the oscillator modules I got for the wine glass project, a rotary encoder is a great choice. I salvaged a nice encoder from a VCR. The center part is a knob for the rotary encoder that rotates continuously. The outer ring can rotate right of left by about ¼ turn. I may be able to use it for reset or some other function.
The downside of this salvaged encoder is that it has a flat flex cable (FFC) connection with 0.05" pitch. I could have soldered wires to the FFC, but this doesn't always work very well or provide reliable connections.