Control Eurorack Synthesizer with Flipper GPIO

#1

I have some Eurorack synthesizer equipment that I would like to control with my Flipper. Specifically, I want to connect the Flipper’s GPIO to Eurorack Control Voltage (CV) inputs. Then I will program the Flipper to modulate the GPIO in response to radio signals and all the other fun things it can sense, so the synthesizer responds to the environment it senses via the Flipper. I’m trying to figure out if this will work with direct connections, or if I’ll need to do some external processing to get a compatible signal

Eurorack CV uses a 5V or 10V range over 1/8" (3.5mm) TS patch cables. Common voltage arrangements include -2.5V to +2.5V, -5V to +5V and 0V to +10V

Flipper’s GPIO is a"3.3 CMOS Level, Input 5V tolerant, Up to 20 mA per digital pin." Does this mean it can do -3.3V to +3.3V? That would give me a 6.6V range to work with, which should be plenty.

There are some projects that connect Arduino to Eurorack. Do Arduino expansion boards/tools generally work with Flipper?

Finally, are there any Flipper community projects around Eurorack CV (or MIDI) that I should be aware of? Searching this forum and the discord didn’t turn up much.

1 Like
#2

It sounds like you need an analogue output whereas the gpio of the flipper are digital.
A rule of thumb you can use: if a Arduino needs a axpansion to do something the gpio of the flipper won’t cut it (although there are some exceptions)
I don’t know the specific logic levels of the flipper but I can tell you what I know.
“3.3 CMOS Level” means it uses a voltage between 0v and 3.3v where (and this varies slightly per chip) if the voltage is below 0.8v it is seen as a logical 0 or low and when the voltage is above 2v it is seen as a logial 1 or high. link
“Input 5V tolerant” means you won’t fry the flipper when you input 5v (and it would register as high in this case)

For the Arduino expansion boards it depends, you will probably have to write your own library’s to support them but it might not be possible at all if the board needs analogue pins or just more gpio pins than the flipper has. It also helps if it is 3.3v Arduino expansion altough it might be possible to use the flipper to interface with a 5v Arduino expansion board depending on the logic levels for 1/high it uses (some might not see 3.3v as high) or if it pulls more than 20 mA on a digital pin.