Synth me up is a synth I built for myself, to get weirder sounds that I usually do from my accordion.
You can enter whatever signal you want on both inputs.

It’s relatively simple, yet fun to play and you have a lot of parameters to sculpt your sound. FM, filter and transposition among others.

the controls are on the left side from top to bottom:

Waveshape: The button let you cycle through 4 waveshapes (sine, square, triangle, ramp)
Filter freq: low pass frequency filter shape
Filter Q: let you adjsut the Q of the filter
ADSR: let you shape the envelope
Dry/wet: let you dial in your clean sound if you wish

In the middle:
Env-ADSR switch: the enveloppe of the sound is either determined by an enveloppe follower or and ADSR. Puhing the button will light a pixel next to the Envelope follower or the ADSR buttons so you’ll know wich is active. Bonus light! There is 2 pixels that show both enveloppe
Env rise: you can adjust the rise of the enveloppe follower
Env fall: you can adjust the fall of the enveloppe follower
Verb mix: you can mix the amount of reverb you want!

On the right side:
FM val-ADSR swich: you can dial in 3 differet FM modulation. 1st is a fixed frequency that you can adjust, for ring mod-esque tones. 2nd substract the ADSR from the fixed frequency and 3rd adds it.
FM freq: let you choose at wich freq the FM will occur
FM mix: the amount of the FM modulating the oscillator

transpose: let you transpose the pitch of the oscillator relative to what you are playing. The transposed pitches are 2octaves below, 1 octave below, 1 fifth below, unison, a fifth over and an octave over. You can change the values on the sequencer on page 3.