Field notes

Things worth trying. Results worth keeping.

Worked examples, explicit assumptions, and sources you can inspect.

reference

3.3 volts is not a personality trait

Separate chip supply, board input, logic levels, and measured voltage before deciding two modules belong together.

reference

Read I²C addresses, pull-ups, and rise-time constraints before turning a bus problem into a firmware rewrite.

methods

Build an operating-state budget and keep nominal battery arithmetic separate from measured runtime.