Tactile feedback is an essential element of any user interface, any keypads are no exceptions. Whether it’s a standalone keypad or a keypad in human machine interface (HMI), tactile feedback can reducing input errors by notifying users when their keypress was registered. As you may know, tactile feedback is a physical response to a keypress. When you press a key, the keypad will respond by some form of physical sensation that you can feel. So, how do silicone rubber keypads produce tactile feedback exactly?

How Touchscreen Devices Produce Tactile Feedback

Touchscreen devices typically produce tactile feedback using vibrations. When you touch an icon or digital key, the device responds by vibrating. It’s not a forceful vibration. Rather, it’s just enough to let you know that the device registered your command. And as a result, you are less likely to press the same icon or key twice, believing that the device didn’t register your command the first time.

How Silicone Rubber Keypads Produce Tactile Feedback

Silicone rubber keypads generally don’t use vibrations for tactile feedback. Instead, they produce their own natural tactile feedback using the compression properties of the webbing. What does this mean? To better understand how silicone rubber keypads produce tactile feedback, you must look at the way in which they are designed. A typical silicone rubber keypad features a switch button over conductive traces or contacts, which is separated with webbing material. When you press the switch button, the webbing deforms so that the bottom of the switch makes contact with the conductive traces underneath. This allows for the completion of a circuit, essentially telling the device that you pressed the key. But when you release the key, the webbing material reverts back to its original position.

Tactile feedback is produced when the webbing material reverts back to its original position. It’s a lighter form of tactile feedback than the vibrations produced by touchscreen devices, but it’s still more than enough to protect accident input errors. Releasing the key on a silicone rubber keypad creates a “snap” that you can both hear and feel. It’s a subtle form of tactile feedback, but it serves its purpose just fine.

The tactile feedback performance of a silicone rubber keypad is dependent upon the webbing material from which it’s made. The webbing material must allow for deformation when the key is pressed, yet it also must revert back to its original position when the key is released. If this doesn’t happen, the silicone rubber keypad won’t produce any noticeable amount of tactile feedback.