What Is 'Travel Distance' in Keypads?

When shopping for a keypad, you may come across travel distance. It's a specification used in most keypads. Whether you're looking to buy a mechanical keypad or a silicone rubber keypad, it will likely have a specific travel distance. What is travel distance exactly, and how does it affect keypads?

The Basics of Travel Distance

Travel distance refers to the distance between the electrical contacts in a keypad. Each key has a set of electrical contacts. There's typically one electrical contact under the top layer of a key, and there's a second electrical contact on the bottom layer. In the keypad's default state, these two electrical contacts will be separated.

When you press a key, you'll push the top contact into the bottom contact, which will allow the keypad to register your command. The two electrical contacts will essentially touch each other, thereby completing the circuit. Removing your finger from the key, conversely, will result in the top electrical contact pulling away from the bottom electrical contacts. The distance between these electrical contacts is the keypad's travel distance.

For most keypads, travel distance is measured in millimeters. There are keypads with a travel distance of just 0.5 millimeters, whereas others have a travel distance of 1.5 millimeters.

Travel distance is also known as key travel. Both travel distance and key travel refer to the distance between the electrical contacts.