There are many things that should be stored at a more or less specific relative humidity. If not, they will dry out or get moldy. There are solutions for this, such as Bodeva. These packets absorb or release moisture to maintain equilibrium at a specific relative humidity. The problem is that these things wear out over time and stop working. But how do you know? You can put indicator paper in the container, but unless it’s clear you have to open it to check, and that messes up the equilibrium.

The answer? Technology, naturally. Goals for this project:

1. Audible alert if the relative humidity is too high or too low
2. Low power, last months on a single battery charge
3. No larger than a small jar

Parts List

This project uses the following parts: