Printer Model: Ender 3 S1
I’m using Klipper on an Android box running Armbian, but I don’t have any GPIO to use and have a spare Pi Zero. Can I use it as as a secondary MCU? All the guides that use Pi as a secondary MCU also host Klipper on it.
No, you need to use an actual MCU. There’s no way to connect a second computer like a Zero.
I think, it shouldn’t be a problem to use your Pi Zero as second MCU. Sineos did this Raspberry Pi Pico + ADXL345: Portable resonance measurement
You may ask him.
That’s Pico, completely different hardware.
A Pico is a breakout board for the RP2040 MCU. It’s designed to do things just like this. A Zero is a single board computer with an ARM CPU. They have very different hardware and very different uses.
Sorry, I forgot this for a while. But now, I’m still thinking about this thread.
Kaan asked, if he could use the Zero as a 2nd MCU to connect his ADXL345.
I think he could hook the Zero using USB to his “Android box running Armbian” as a second MCU and connect his ADXL345 like this
What do I miss here?
Kind regards, hcet14
Klipper can’t utilize Zero at all this way. It has to be either a Pico or everything needs to run on Zero.
Correct 
Basically quite simple. At present, two “things with Linux on it” cannot coexists in such environment.
