Arduino and related technologies have revolutionzed scientific instrument making. Things that were either "too hard" or "too expensive" are now straightforward for hobbyist and non-technical scientists.

For example, I build automated microscopes as a hobby and I use arduino products (well, used- now I use ESP32 with micropython, but that still depends on the Arduino API) and it's been tremendous for building high speed interfaces (I need to blink an LED at the same rate/in sync with a camera shutter opening/closing) . Even when I do photography, I'm still building arduino and other related things to help automate the tedious bits. And when that gets boring, I take out my guitar and use arduino or similar products to do audio processing in realtime.

For many of the things I want to do, there is no product on Amazon, or it's obscenely expensive (XY stages typically cost $10K and up).