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Capacitive Keyboards - resistant to acids and dirt
Hoffmann + Krippner GmbH
By entering into the new technology of capacitive keyboards, Hoffmann + Krippner increases its product list by robust input devices for high mechanical load.
The systems are resistant to acids, dirt and other contaminations. No mechanical wear of the contacts takes place, cleaning is easy, ensures maximum hygiene standards and guarantees a high chemical resistance (for example when placed behind glass).
The even surface allows for comfortable handling without pressure and by only slight touches. The missing tactile feedback can be replaced by optical and /or acoustical signals. The technology allows for flat designs and is applicable behind glass, plastic or other insulating surfaces. Any type of keys are possible.
The wiper’s sensor surface consists of two surfaces isolated from each other (sending and receiving electrode). Short bursts are sent to the sending electrode. These bursts get to the receiving electrode through the front (dielectric) and are added up in a sampling condenser.
By applying a finger an additional condenser forms, which gathers electric charges and reduces the available amount of charges for the sampling condenser. This procedure is detected and returns an output signal. Digital filters and adjusted algorithm make sure that glitches as well as changes (rain, mist etc.) don’t lead to any malfunction.