How long can you keep an Arduino circuit running on three AA ... The design uses a DS18B20 temperature sensor and a Nokia 5110 LCD display. It also uses a photoresistor to shut off the LCD display ...

It can run on the Uno, Nano, Pro Micro, or even home-brew Arduino boards. He’s demonstrating the program with a Nokia 5110 LCD, but has also included code for the typical 2×16 LCD displays.