Interesting new stuff from Apple! According to AppledInsider.com:
A recently published patent application from Apple reveals the company has looked into a flat keyboard that would detect acoustic pulses from users’ taps instead of relying on physical key presses. (1)
Apple’s new keyboard apparently relies on both a captive touch sensor and a piezoelectric sensor or sensors.
How does a piezo sensor work?
Sensors are intermediaries between the physical world and systems that electronically process and store information: a sensor accepts a particular physical, chemical, or biological input, converts the information into an electrical signal, and delivers the signal to a data processing system.
A piezo sensor will generate an electrical signal when it experiences a change in the applied force or pressure. Under a static input, free charge carriers in the ceramic element migrate toward the dipoles, neutralizing the charges on the dipoles and thus effectively electrically discharging the ceramic element. The charge will also drain across the input resistance of the device used to measure the signal from the sensor. A stress upsets the balanced state and restores an electric charge, but if the stress is maintained the charge will drain again. Polycrystalline ceramics, manufactured by APC International make superior force and displacement sensors because they exhibit high mechanical strength and are fairly resistant to adverse environmental conditions.
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