In this video we build yet another temperature monitor using a DS18B20 temperature sensor. But this project is different. It can last on batteries for almost 1.5 years! Yes! Using the Arduino low power library, we can have this project running for a long time.
A major benefit of microcontrollers like the ATmega328 featured in the Arduino Uno when compared with microprocessors is that they are capable of operating under some very low-power conditions. Just how low-power is up for debate, but Nikolaos-Sotirios Koumaris has put considerable effort in to working out just how far you can go. As brought to our attention by Hackaday, Nick has produced an Arduino circuit which uses a temperature sensor and Nokia 5110 liquid-crystal display to show the current temperature of its surroundings. Unlike most similar projects Nick has worked to draw the power usage down to a bare minimum, sleeping the Arduino between temperature reads and even using a photoresistor to switch the display off if the room is dark. The result, he calculates, is an Arduino sensor platform which can run for over a year on a set of three rechargeable AA batteries - and while he hasn't run the circuit for that long to prove his workings, a bundled power consumption spreadsheet included in the code download makes a convincing argument. Full details of the components and code used are available in the description on Nick's YouTube video.