LM35 Analog Thermometer with Arduino

10 mV per degree Celsius, straight out of a TO-92 — the simplest electronic thermometer you can build.

Difficulty: Breadboard. Estimated build time: about 20 minutes. Estimated parts cost: about US$3.80. 3-part bill of materials with live supplier pricing. A thermometer that reads air temperature in Celsius using the LM35 — a three-pin sensor that outputs an analog voltage proportional to temperature with a 10 mV/°C scale factor and a 0 V offset.