“A very low power consumption rechargeable temperature and humidity monitor that can run off a rechargeable battery for 12 days or more.
I needed a temperature and humidity sensor that would show maximum and minimum levels recorded so that I could monitor the levels in my greenhouse. I do not have any power in the greenhouse so the aim was to reduce power consumption as much as possible so that it could run on a rechargeable battery for long periods.
The solution to this was to have the Arduino enter a low power state for a period before waking and taking new reading then repeating the cycle. To achieve this I used the rocketscream low power library to put the processor to sleep, waking every 24 seconds to check the temperature and humidity, which takes less than a second.”