Keypads

A keypads is a collection of small blocks or pads of buttons and numbers that provide a user interface to a machine, cell phone, calculator, etc. Buttons usually display numbers, symbols, or letters and can be used when information needs to be entered. For example, on a calculator, enter a total via the keyboard or select the desired item from a vending machine. Standard keypads have 0-9 buttons or on/off functions, while other keypads may be blank and offer customizable functions with words and symbols.

Types of Keypads:

If your human-machine interface (HMI) doesn't have a touchscreen interface, you'll likely rely on a keypad that allows operators to enter commands. However, not all keypads are created equal, as some keyboards have different technologies.

• Membrane keypads:

One of the most popular keypads is the membrane, commonly found in consumer electronics and commercial applications. It usually consists of three layers:

Top layer - Label and keys printed on the front.

Spacer layer and back layer - with conductive strips.

• Dome-Switch Keypads:

A combination of a flat panel membrane and a mechanical switch keypad, widely used in commercial applications, with a dome switch. Two printed circuit tracks are integrated under a silicone keypad with a dome-shaped switch. These domes create tactile feedback when pressed, making them especially useful in commercial and work-related applications. Additionally, dome switch keypads have a high level of reliability and often last up to 5 million cycles.

• Scissor-Switch Keypads:

The third type of keypad features keys designed like scissors, living up to its name. The scissor-switch keys consist of two separate pieces of plastic that fit together like scissors. It also features a rubber dome-like dome switch keyboard, but the scissor design improves functionality by keeping the keys connected.

However, including the cost, the scissor keypad has several potential drawbacks. You can expect to pay more for these than a membrane or dome switch. Additionally, dirt and debris can get stuck under the keys, shortening their lifespan if not cleaned regularly.

• Capacitive Keypads:

Capacitive keypads use capacitive technology to register key presses. Pressing a key changes the capacitance of the capacitor pad. They are designed with foam keys, usually finished in aluminum. Although capacitive keyboards are not as popular as membrane keyboards, they are still viable choices for specific applications.

What is the difference between a keypad and a keyboard?

A keypad features keys used primarily for touch input on a machine, while a keyboard is a set of keys ideal for operating a typewriter, computer, etc.

Applications:

Keypads are found on devices that require mainly numeric input, such as 

• calculators,
• vending machines, 
• ATMs, 
• point of sale terminals, 
• television remotes, 
• push-button telephones, 
• combination locks, 
• safes, and 
• digital door locks.