Knobface Controller
I was looking for a small midi controller with a fair number of knobs to accompany my Akai APC20. However, the only controller out there primarily with knob-based controls was the Behringer BCR2000, which was a bit excessive for my uses. The other alternative was the Kenton Killamix Mini, which was just flat out expensive. Thus, I decided to build my own controller, as I also had been meaning to start learning some DIY electronics stuff.
The Knobface, named as such due to its its front panel resembling a face, features 8 rotary encoders (1 with a pushbutton to switch through the 4 control banks), 8 rotary potentiometers, 1 slide potentiometer as a crossfader, and 2 LEDs used as a control bank indicator. The microcontroller is a Teensy 3.0, chosen for its low price point, its decent number of inputs and outputs, and support for USB MIDI.
The encoders also have a Increment/Decrement Mode using NRPNs, but as support for this is inconsistent among DAWs, this mode can be turned on or off as required.
Overall, the Knobface cost about $150 to build, which is a bit pricey when an equivalent controller from a major manufacturer would cost about a quarter to a third less, but then price wasn't really the main point anyway.
Components list can be found at the bottom.
Microcontroller: PJRC Teensy 3.0
USB Panel Mount Adaptor: PJRC USB Cable, Micro-B to Standard-B Panel Mount Adaptor
Enclosure: Multicomp AB77W
Feet: Hammond 1421T2CL
LEDs: Ledtech L4RR5000H1D1
Resistors: TE Connectivity LR1F15R
Rotary Encoders: Bourns PEC11-4020F-N0024
Rotary Encoder w/ Pushbutton: Bourns PEC11-4020F-S0024
Rotary Potentiometers: Bourns PTV111-3420A-B103
Slide Potentiometer: Bourns PTA6043-2015DPB103
Fader Knob: Multicomp CP-L175
Rotary Knobs: Multicomp CR-R4-1
The links will lead to PJRC, Element14 or RS Components. The parts can probably be found elsewhere as well.