Nick Hyde's Dial to MIDI CC device is very straightforward. Simply specify a MIDI CC channel, and turn a dial to generate MIDI CC data.
MIDI CC data is part of the MIDI languate that allows synths to receive all sorts of automation channels. This device was created by Nick Hyde to generate MIDI CC data while developing other devices, but it functions as its own useful device. For example, you can control the sustain, volume, breath, and other expression parameters on a synth with this device.