DHT11 Temperature + Humidity Logger

A single-wire sensor and an Arduino sketch print room temperature and humidity to the serial monitor every two seconds.

Difficulty: Breadboard. Estimated build time: about 30 minutes. Estimated parts cost: about US$3.50. 4-part bill of materials with live supplier pricing. A combined temperature and humidity logger built around the DHT11, a tiny 4-pin sensor with an integrated capacitive humidity element and an NTC thermistor.