Using the tilt of an iPad to control an analog feedback-based patch.
In this patch, I send OSC (Open Sound Control) data about the tilt of my iPad to Max/MSP on my computer, which converts this data into MIDI, and subsequently, on my synth, voltage. That voltage (changing based on the iPad’s tilt) opens up a VCA (voltage-controlled amplifier) which controls the level of the feedback.
The analog feedback loop here goes: ring-modulator to saturator to reverb to delay to low-pass filter to the VCA (which runs back into the ring-modulator).
More digital control of analog Eurorack here: