DIGIPOT instead of regular Expression Pedal - Arduino Project

I've been toying with this idea to use a Digipot instead of a regular expression pedal. A normal expression pedal uses a normal potentiometer that you control with your foot, a digipot is just a digital potentiometer that you can control with an Arduino, for instance.

Last year I've posted a video where I've used the digipot on an OctaFuzz, where the pot controls the amount of octave in the fuzz. I've decided to split those two projects where I've installed a TRS jack onto the OctaFuzz so you can control the octave with an expression pedal. The other project is to create a virtual expression pedal with the digipot. Since I've already made a footcontroller for the Boss RC3 Loopstation using an Arduino and housed this in this red enclosure, there was enough space to put in the digipot as well.

This device has 4 modes:
- Mode 1: Static, expression in = expression out. The incoming expression data is read through the analog input of the Arduino. The output of the digipot matches the input.
- Mode 2: Saw wave. The expression output slowly goes from 0% to 100% and restarts when it reaches the high point.
- Mode 3: Triangle wave. Expression output slowly rises from 0% to 100% and falls back slowly again.
- Mode 4: Square wave. Expression output alternates between 0% and 100% and nothing in between.

Without MIDI tempo, the incoming expression sets the rate of the wave shapes in mode 1, 2 and 3. With MIDI tempo, the LEDs blink and the waves are synchronized to the beat. You can set it to a length of 1, 2 or 4 beats. Reverse wave shapes are also available on modes 1-3 when MIDI tempo is received. Without MIDI, reverse is only available on mode 1, so it becomes a falling sawtooth. Mode 1 is always independent of MIDI tempo, although the other LEDs blink on the beats.

Chapters:
0:00 Intro jam
0:39 Project background
4:03 Modes without MIDI tempo
7:32 MIDI sync
11:18 Code explanation: setup and button behaviour
13:34 Code explanation: MIDI sync
19:10 Code explanation: without MIDI

[DynamicRockers]

Thanks! This is exactly what I was looking to sync a vintage delay rack to midi clock from its VCO pedal input. Excellent job mate ;)

[JoeBrown]

This is insanely cool, been looking for something just like this totally gonna explore making something like this!

[stephenhookings]

Excellent work and demonstration of cool idea.

[PaulTheSkeptic]

There's another one. I forget what it's called but it's awesome. It's red.

[kingpishful]

Which sketch is for this on the GitHub? Or do I add all 3?

[captain]

How can i implement a version of this without midi? I just need a basic clone of expression ramper actually, one knob for rate and thats all.