Stop worrying about turning your bathroom exhaust fan on and off. Instead, install a humidity sensor that automatically controls the fan switch.

Or at least a window! Using the case of an air freshener, a simple DHT11 Humidity/Temperature sensor, an LCD, a 12V fan, and ATmel328 microcontroller, he created this handy gadget.

Adding this board (translated) to your bathroom fan will turn it into a smart device. It’s designed to automatically shut off the fan after it’s had some time to clear humidity from the… ...