The Simple DIY Device Can Detect Moisture on Your Face Mask

Despite the fact that businesses are reopening in some areas — and possibly because of it, the coronavirus pandemic rages on. If you are going out and visiting those businesses, you should absolutely be wearing a face mask whether it is required or not. But there has been a lot of push back against face masks, particularly in the United States. The argument is generally that they’re ineffective or uncomfortable. We're not going to address the efficacy of face masks, but the Mask Moisture Meter could help ensure that wearing one is as comfortable as possible.

If you think a fresh, brand new face mask is too uncomfortable to wear, then there isn’t much anyone can do to change your mind. But if you find that your masks become more and more uncomfortable as time goes by, moisture could be the problem. The air that you exhale naturally contains moisture, and that can collect on the fabric of your face mask over time. If the mask gets damp enough, it can cause chafing and could potentially even make it harder to breathe — though it should never cause significant breathing problems. Some masks have special valves for exactly that reason.

For standard face masks, at least of the reusable variety, the Mask Moisture Meter can notify you when the fabric has become damp. This simple device is built entirely with a single 555 timer and a few passive components, and doesn’t require a microcontroller or any special sensors. All it does is measure the resistance of the mask fabric. If the mask is dry, a green LED will stay lit. If the mask is damp, it will blink a red LED and sound a piezo buzzer. The more moisture, the faster the LED blinks and the higher the pitch of the buzzer. The components are mounted on a custom PCB and fit inside of a 3D-printable enclosure that attaches directly to your face mask.