Choose a board for the project

Start with the requirements

List the sensors, actuators, communication interfaces, timing needs, power source, and physical size. Check how many pins and which peripherals the design actually uses before choosing a board.

Verify the exact model

Classic Uno and Nano AVR boards are common 5 V learning platforms, but product families have multiple revisions and compatible clones. ESP8266 and ESP32 boards add Wi-Fi features and generally use 3.3 V GPIO. Seeed Studio XIAO SAMD21 is a compact 3.3 V board. Check the exact model's official pinout, analog limits, power ratings, USB interface, and software package.

The board's input-power rating and GPIO voltage tolerance are separate specifications. Never infer one from the other. Confirm library and board-core support for any sensors or communication features your project depends on.

Make a small proof first

Before building the full device, compile and upload a minimal example, read one sensor, and test one output through its proper driver. This catches board selection and wiring assumptions while the circuit is still simple.