Electronic – Rubber push-button

buttoncomponentsswitches

On lots of electronic devices, such as this Korg drummachine/sampler,

enter image description here

there are some soft rubber push buttons.

What are they called? (I'm looking for the most common name, so I'll can find them easily on eBay or any electronic-parts-shop)

How do they work? (and if on topic, are such rectangle pushbuttons easy available?)

Best Answer

It's a silicone rubber keypad. They're usually custom-made for the application (MOQ in the thousands or more if a mold has to be made).

http://www.interfacetech.com.cn/Upload/image/vit-r-0018.jpg

They require a matching PCB that is either gold-plated or printed with a carbon paint in order to form the key patterns. The rubber keys have a conductive silicone bit molded into the back of the keys that bridges the PCB interdigitated pattern so that the switch is closed (the resistance is not nearly as low as with a switch that has metal contacts, but plenty good enough for a microcontroller to detect). The buckling of the key gives a tactile feel that is appropriate. Sealing against the environment (water, finger oils etc.) is not great, but acceptable for many applications.

http://www.haeusermann.at/sites/default/files/styles/content_image_lightbox/public/articleimages/capacitive_keyboards.jpg

Excellent choice if you're making a large quantity of a product, not so practical if you're only making a few hundred pieces or fewer.

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