How to make PCB silicone button contacts

[silverhawk_184]

Hello,

I have been looking everywhere on how to make those black conductive contacts that silicone rubber buttons make contact with. Like the ones in video game controllers (which are some how pressure sensitive), phone keypads, tv remote controls, etc.

Does anyone have any ideas? or know what the name for them are?

Thanks

 

[trident9]

Don't know what they are called, but I believe they are carbon granules bonded to the printed circuit board. It may be possible to make them with carbon filled epoxy if such a thing exists.

 

[crutschow]

The ones I've seen appear to be a black, dense, conductive foam which makes contact between two adjacent semi-circular pads on the PCB when the button presses the foam against the PCB. Here's an article on making such devices.

 

[silverhawk_184]

This is awesome. Thanks for the link.

 

[robot guy]

Qtc

The best I can think of is quantum tunneling composite. It is a wierd material that changes resistance from very high to very low when pressure is applied. You used to be able to buy it in 2 or 3mm 'pills' from mapln however they seem to be discontinued. Like the stuff used in the PCB switches it is a grey-black colour.
Quantum tunnelling composite - Wikipedia, the free encyclopedia
here is a wikipedia link explaing more.

 

[nsklavos]

**broken link removed**