Large, flat, flexible waterproof button?

Question

I'm working on a ski helmet audio project, with a stereo bluetooth headset (Motorola S305) circuit wired in.

I'd like to have large buttons on the outside of the helmet, to be activated by gloved fingers.

The buttons are the trickiest part since they'd have to be big, stick securely to the helmet, and resistant to moisture.

I saw Ben Heck wire buttons under foam on a microphone, which is nice since it sidesteps making a button from scratch.

I also found this thread which suggests using sticky foam pads and tin foil:

http://forums.benheck.com/viewtopic.php?f=20&t=23041

I'm curious about people's experiences with different types of foam, esp. foam that might be waterproof. I also wonder about making a sandwich of foam and (a) foil with a spring of some kind or (b) an off-the-shelf button and coating it all, maybe in latex, to seal it up.

Any suggestions would be most appreciated!

Thanks,

-Jeff

jmsarduino.blogspot.com

jmsaltzman · Accepted Answer

I came up with a good solution using a stack of adhesive-backed craft foam pieces, cut to surround a clicky 12mm square button in a sort of stepped pyramid. The bottom piece of foam stuck very well to the helmet surface, and foam above that which didn't stick as well to the foam below got a bead of hot glue around the edge. They're plenty water-proof since I hot glued any place water could get in. A small Case Logic hearing aid case attached to the goggle strap on the rear of the helmet holds the electronics-- bluetooth board, connections, battery and charger circuit; appropriate since it's a sort of hearing aid The project is complete and the helmet has had two glorious, rocking days out on the slopes. It works just like I'd hoped, giving me full remote control of my iPhone with gloved hands while flying down the mountain. I got plenty of funny looks and people asking "what's up with your helmet?" I'll post pictures and a demo video soon, thanks for the replies!

Former Member · Answer

I used some thin white flexible (I think PE) protective wrapping foam to replace defective foam from a car horn switch - the basic configuration was metal plate with nubs , foam insert with holes for the nubs, metal plate. The foam was about 1/8 to 3/16 thick, and compressed enough without a great deal of force for the metal to make contact.

The plastic wrapping foam was totally waterproof - a good choice of metal might be important if it wasn't enclosed.