Silicone Rubber Membrane Switch

A silicone rubber membrane switch, also known as a rubber keypad or rubber dome switch, is a type of user interface device used in electronic devices and control panels. It typically consists of a flexible rubber or silicone membrane with embedded conductive carbon pills or metal domes.

When pressure is applied to specific areas on the membrane, these elements make contact with the circuit, completing an electrical connection. Membrane switches are known for their durability, tactile feedback, and customization options, making them widely used in various electronic devices and control panels for their reliable and cost-effective user interface solutions.

A silicone rubber membrane switch typically consists of several layers that work together to enable the switch to function. The top layer is a graphic overlay, often made of polyester or polycarbonate, that displays the labels or symbols for the buttons or functions. Beneath the graphic overlay is a spacer layer, which provides separation between the top layer and the conductive layers below.

These layers contain patterns or traces of conductive material, such as carbon or silver ink, which form the electrical circuit when pressed. The bottom layer is back adhesive, it always used to stick with the end-application.

The operation of a membrane switch is relatively straightforward. When you press a button on the switch, it immediately connects one of the columns to one of the row lines. This allows current to flow between these rows and columns.

For instance, if you press key 1, it connects row 1 to column 1. Similarly, if you press key 2, it connects row 1 to column 2. An Arduino microcontroller is employed to scan these row and column lines to detect which key has been pressed and take appropriate action accordingly.