Help selecting sensor for a simple project: trigger fan from humidity


I want to use a multisensor to detect the humidity in my bathroom and start a smart swith (fan) when it’s needed

For now, I have an aeon multisensor working with 2 batteries.

Is there a better solution? The batteries are draining pretty fast on the sensor and I can’t use a use cable , no close plug


How quickly are the batteries draining? You may be able to change some parameter settings to extend the battery life.

Check out the Monoprice 4 in 1 sensor or the ZooZ 4 in 1 sensor. Note through that the battery life is between 2 and 6 months depending on the configuration and they run on 2 AAA batteries. If you decide to use AAA 1.5v lithium batteries instead of alkaline, it’ll roughly double your battery life.

Had to change the 2 CR123 twice in less than 2-3 months

Those 2 sensors integrate well with ST?

Thanks for the advice

There’s also the Aeotec Multisensor 6 that can be powered by USB if you have an outlet close by. It’s a little pricier but can be offset by no long-term battery cost :slight_smile:

I just ordered the new version of this. Should be here today. Supposedly has better battery life and quicker motion response.

1 Like

Thanks for all your answer

I’m using Xaiomi humidity sensors. They are small and use very little battery. Quick to react. Also they are 15.00 CDN so about 2 Big Mac’s USD.

1 Like

I use Xiaomi sensors in my bathrooms, too. Battery life is usually ~9 month.

I recommend you put an additional sensor in a central area of your home. This way you can trigger the fan based on the humidity difference rather than an absolute measurement. Overall humidity is usually lower in the winter than in the summer and so the fan will only run when it is needed.

just ordered Xiaomi !

Thanks for your advice on the trigger