Nice method and analysis. The temp sensor 3 pin devices are simple and cheap but good for 0.5 deg C precision or nearly a full degree in human measure.

The device is simple — it uses an Arduino Nano hooked up to a thermistor to measure the temperature of fluid in a pot. ... and you can use this fact to make a temperature sensor.

The Arduino Plug and Make Kit has at its core an Arduino UNO R4 board with Wi-Fi, ... a motion sensor, a simple buzzer/speaker, a temperature/humidity sensor, and three simple buttons.