Keypads are an essential component used in computers and human machine interfaces (HMI) alike. They offer a method of input, allowing operators to enter commands and perform operations on the connected device. There are two primary types of keypads used for such purposes, including mechanical and membrane.
Mechanical keypads are the traditional variety, featuring keys which are separate moving parts. They are cheap, easy to produce, and readily available, making them the preferred choice by many computer companies. But an alternative type of keypad that’s become increasingly popular in recent years is membrane. Unlike its mechanical counterpart, membrane keypads feature a single unit whose keys are not separate moving parts. Instead, it’s an entire membrane in which the keys are embedded.
Now that you know a little bit about the differences between mechanical and membrane keypads, you might be wondering how the latter actually works. While the actual design varies depending on the manufacturer and its specifications, most are comprised of several different layers consisting of a top membrane layer, an inert layer, a bottom layer, and then conductive tracts underneath them all. Typically, the switch on a membrane keypad is left in the open position, simply because the electrical current is unable to cross the non-conductive inert layer. But when a user presses down on a key, it allows the upper and bottom layers to make conduct; thus, completing the circuit and allowing the electrical charge to flow. When this occurs, the switch changes from open to closed, at which point the connected device identifies the key press.
The most distinguishable characteristic of a membrane keypad, however, is its keys, which are all a single component and not separate moving parts. Designing a keypad in this manner offers several notable benefits, one of which is increased strength and durability. Mechanical keypads have a tendency to break down over time, due largely in part to dust, dirt and debris becoming embedded underneath the keys. But membrane keypads don’t suffer from this problem, as the keys are embedded into a single component. Membrane keypads also offer greater ergonomics, reducing strain and tension for the end user.
If a membrane keypad the right choice for you? It really depends on your intended application for the keypad. There are both pros and cons associated with mechanical and membrane keypads, but the latter is becoming more and more popular among business owners for commercial applications.