[theamk]

You start with interfacing with well-known, well-documented hardware devices (say anything from Adafruit or Sparkfun), then move to interfacing with rare devices with badly translated manuals and broken example code (many cheap sensors), and then to reverse engineering.

It helps if you use non-trivial hardware: while plugging STEMMA/Qwiic cables make for simple and reliable hardware, having a nest of wires on protoboard will teach you to how to trace connections and use multimeter/oscilloscope.

Also for reverse engineering, some devices are much easier than others. For example serial ports on various embedded linux devices are probably simplest - you might not be able to do anything useful, but boot logs are often very easy to discover, you don't even need oscillosope/logic analyzer.

The next step is simple one-way links, like most infrared remote controls or cheap radio transmitters (in OOK mode) - easy to capture, and fun (if tedious) to decode. There is a danger that device you pick will turn out unexpectedly complex, so don't be discouraged if you have to give up on one device and pick a different one.

[jonwest]

This all makes sense, thank you for all of the info!