BME280 Temperature / Humidity / Pressure Node

A single Bosch BME280 chip on I²C reads three weather variables at once — your first real environmental sensor that is good enough for actual data.

Difficulty: Breadboard. Estimated build time: about 35 minutes. Estimated parts cost: about US$14.50. 4-part bill of materials with live supplier pricing. A weather node built around the Bosch BME280 — a 2.5 mm × 2.5 mm sensor that reads air temperature (±0.5 °C), relative humidity (±3 %) and barometric pressure (±1 hPa) and reports all three over I²C or SPI.