If you are designing a product that will use the helpful and versatile rubber keypad, it is important to not only pick a useful, functional, and attractive look, it is also essential to select the right type of contact to go under the keypad. Here's a snapshot look at the types that are available: the ultimate success of your product will depend on your choosing the perfect one.

The Carbon Pill

The most commonly used contact, the carbon pill is - as its name implies - circular shaped and comes in sizes ranging from 2.0 to 8.0 mm in diameter. They are fairly slender in terms of thickness, measuring less than .5 mm. The reason why the carbon pill is so popular is because it enjoys a long life. This longevity is due in large measure to the fact that is has low contact resistance and quite simply doesn't wear out as fast as others as a result.

Silk Screened (Conductive Ink)

This contact type is incredibly versatile since the ink can be screened onto virtually any sized contact switch area. The contact resistance for this type of contact is low at first, but as the microns-thin ink wears away the resistance becomes increasingly higher. Because of this factor, conductive ink does not enjoy the same longevity as the carbon pill. It may be the best electrical solution for your particular application, however, and in this case it would be an excellent choice.

GRSP

Combining the best of both the above types, the GRSP contact provides both carbon pill-type contact resistance as well as the flexibility of conductive ink technologies. Unlike ink that has been silk screened, special conductive ink for GRSP contacts is applied thicker which gives the contact a longer life.

When it comes to creating the ideal keypad that is completely user-friendly the right type of contact just might make all the difference.