In this project we are looking for a solution to control the humidity level in the bathroom. In particular we will try to control an already present fan that is operated manually. You can of course buy a fan with an integrated controller, but this is often expensive and with limited manual settings, here we’ll see how to build one!
The controller has the following functions and options: it measures relative humidity and temperature (via the BME280 sensor), turns on a fan (with a relay) and turns it off when the humidity has dropped. It is also possible to keep the fan on for a selectable time after the humidity has dropped. Everything is controlled by an Arduino Nano.