Tips for designing modules with arduino?

Hiya! I'm in the process of making my first own module. I think using the Atmega 328PU is a common and popular way of making fairly complex task without having to design complex analog circuits. Examples such as the original ALM Pamela, 4ms PEG, Mutable Instruments Grids, Bastl Kompas etc really show this potential.

Now, are there any common tips when designing such machines? Is there a common rule for all arduino projects? What are some pitfalls that you got into when sketching?

I am building a trigger sequencer for the 1u row. Using trigger inputs it will read from a buffer and decide wether or not to output a trigger.

Thankful for absolutely any tips. :-)

I'd look at the mi branches code - should have almost everything you need there

I'd recommend to use Arduino as a platform to practice and understand the basics but at some point the processing power and limitations of an 8-bit processor will make you hit a roadblock depending on what your goals are. On the other hand the ARM-environment is great and cheap, check out the blue pill/black pill boards. No wonder why so many digital modules have M3s and M4s inside. (Varigate, QuadLFO have ARM processors, Mutable Instuments uses them in a lot of modules, list is endless...). You can get ARM boards for 1-3$ from China (check out AliExpress).

Now, are there any common tips when designing such machines? Is there a common rule for all arduino projects? What are some pitfalls that you got into when sketching?
-- Wiktorion

If you need CV output you need a proper MCP49xx DAC, the Arduino pcm outputs won't do it. There is an Arduino SPI Lib available for this. Arduino is nice to tinker around but I have read somewhere that Mutables Émilie classifies 8bit controllers as waste of time because you hit the limits very soon.

Btw this is my Atmega project: https://www.modulargrid.net/e/gezeiten-ultima-ratio-2016