Labs Idea #16: Anti-Fogging for Bathroom Mirrors
If you like hot showers, you know the issue of a completely fogged mirror after leaving the shower. There are heated mirrors available, but they heat constantly and therefore waste a lot of energy. With a humidity sensor the heating can be automated and therefore energy consumption can be drastically reduced.
Condensation on the mirror corresponds to a too high relative humidity. By a given absolute humidity of the air, only the temperature of the surface influences the relative humidity. By heating the surface, the relative humidity can be lowered and condensation can be avoided. A foil heater is used for this purpose.
Sensirion humidity and temperature sensors are accurate and fast enough to detect early if someone takes a shower in the same room.
The SHT senses the humidity and temperature of the air. For this simple implementation, the placement is not critical as long as the sensor is not heated significantly above air temperature. The power supply is attached to the bathroom lighting, such the circuit is not powered when nobody is inside the bathroom and furthermore the power-on event can be used as a trigger to preheat the mirror. If that is not possible, some modifications to the event logic are necessary.
A sample implementation can be found here.
Ideally the anti-fogging feature would be combined with a smart mirror which can display information. Please contact us if you plan implementing this or already have.
To improve performance and especially efficiency, algorithm and physical implementation can be improved. Please contact us for support.