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Piezo Switching Technology

Piezo KeypadsDiamondHMI offer a unique range of Piezo Ceramic Switching products including individual Switches and various Keypads and full Keyboards. All utilise patented piezo sensing elements which when incorporated into a metal housing produce a very rugged switch , capable of >50m actuations and sealed to IP68.

The Piezoelectric Effect

A Piezo Switch uses the direct Piezoelectric effect to transform a dynamic mechanical stress into an electrical signal.

This is achieved with a unique patented Piezoelectric unit that incorporates the Piezoelectric ceramic sensor, the electronics that emulate the switching function and, most important of all, the linking anisotrophic conductive rubber that electrically connects the Piezoelectric sensor to the electronic circuit. This special solderless connection is the core of our reliable technology which ensures the long life of the device since no thermal stress is inflicted upon the Piezoelectric ceramic material during assembly.

When finger pressure of approximately 1N/sec. Is applied to the switch's actuation surface, the metallic membrane of 0.6mm thickness bends 0.1.-0.2mm. The Piezoelectric ceramic materials attached on the inside bends accordingly, creating an electrical signal. This electrical signal is conveyed via the anistrophic rubber conductor to the electronic circuit that amplifies and activates the suitable transistors that emulate the functioning of a standard Normally Closed contact.

The entire construction is potted ensuring total impermeability to dust and water ingressing under very harsh conditions - even when submerged.

The Piezoelectric technology therefore provides a sturdy and reliable product with the following basic specifications:

Nominal Switching Current: 0-2 amps
Rated Voltage: 0-35 amps
Contact Arrangement: N.O. or N.C.

Mechanical Tolerance: up to 1000 N/cm
Number of Actuations: >50 million
Operating Temperature -40 to +125 Celsius
Temperature degrading: -25% at -40, +25% at +80 Celsius
Housing Material: Aluminum, Stainless Steel.