Hi all!
We are exploring ways to seal the microphone on the urban board. We want to share with you some insights on the first options we are handling, in case anybody wants to join in the testing process or share some comments.
Microphone Cloth
This was a bit unknown to us, but there are certain types of water repellent fabrics that can help on this. We have learned about this from some local friends in Natural Parks that use the Audio Moth in a simple IP box. Here is how it looks (simply glue it to the box) and voilá:
Here are the links to the material in question:
- Specs: https://sealingdevices.com/wp-content/uploads/2022/10/GORE-Acoustic-Vents-for-Industrial-Applications-Microphones-WEB.pdf
- Buy: https://www.akustikstoff.com/en/Find-the-Right-Speaker-Cloth/Water-Repellent-Speaker-Cloth-2-0-Brown-Beige-128::16052.html
Enclosure
@adaisuri is working on a way to seal the microphone by placing a stretched chunk of plastic film. The manufacturer of the device provides guidelines here: https://invensense.tdk.com/wp-content/uploads/2015/02/Recommendations-for-Mounting-and-Connecting-InvenSense-MEMS-Microphones.pdf
The membrane material should be selected to present as little impediment to sound as possible. A thin layer of soft flexible rubber material is the most suitable for this application. Most measurements described in this application note were performed with a layer of 0.01 inch thick, 35A durometer silicone rubber (McMaster-Carr Part Number 86435K31) used as a seal. Some measurements were also completed with 0.002 inch thick, clear, low density polyethylene (LPDE) film.
So @adaisuri is trying to use plastic film (the same that we use for food at home) to make an enclosure according to the recommendations above. If it all works out after the tests, the idea is to make it easy for us to 3D print and cut a simple chunk of plastic film to protect the microphone from liquid ingress.
If you want to contribute with some testing or have any other ideas, more than welcome!