Capacitive keyboards - resistant to acid and dirt

A major focus regarding the product portfolio at Hoffmann + Krippner is capacitive keyboards. These input units are exceptionally robust and ideal for high mechanical stress 

Capacitive input systems are resistant to acids, dirt and other contaminants. This prevents mechanical wear of the contacts, makes for easy cleaning, ensures maximum hygiene standards and guarantees high chemical resistance (for example when placed behind glass).

The even surface allows for comfortable handling without pressure and using only slight touch. The missing tactile feedback can be replaced by optical and/or acoustic signals. 

The technology allows for flat designs and is applicable behind glass, plastic or other non-conductive surfaces. Keys in any shape are possible.

The wiper's sensor surface consists of two layers isolated from each other (transmitting and receiving electrode). Short bursts are given off the transmitting electrode. These charges go to the receiving electrode through the front (dielectric) and are added up in a sampling capacitor. 

Through the pressure applied by a finger, an additional capacitor forms, which gathers electric charges and reduces the available amount of charges available for the sampling capacitor. This operation is detected as a key operation as it returns an output signal. Digital filters and adapted algorithms ensure that glitches as well as changes in the environment (rain, mist, etc.) do not lead to any malfunctions. 

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