During winter months, humidifiers are crucial to avoid super dry air indoors. I strongly prefer evaporative humidifiers (over mist ones), as they don’t leave residue all over. For years I used two Xiaomi SmartMi Evaporative Humidifier, connected happily to my Home Assistant.
Last month, both of my humidifier (version 1 and verison 2) died: one wouldn’t turn on, the other one would report 100% constantly. I found that it’s, a common issue with these devices. Removing the top part (e.g. for refill) without turning off the humidiifer first leads to failures of water level sensor..
Instead of throwing the devices away, I decided to repair them. I wrote up the guide in mwitkow/xiaomi-humidifier-water-sensor-digispark that describes how to replace the faulty microcontroller with a Digispark ATTiny85 clone.
The process involves a bit of soldering, but it’s a relatively straightforward tinkering project.
Here’s what the power board with the faulty microcontroller (blue box) looks like:
And here’s the pretty hack:
The fix works perfectly, and the humidifier is back to being smart. The GitHub repository has all the necessary code and a detailed step-by-step guide. Highly recommended if you have the same issue and are not afraid of a little DIY.