PICDEM™ Touch Sense 1 Demo Board
Touch sensing is fast becoming an alternative to traditional push-button user interfaces, because it requires no mechanical movement, and enables a completely sealed and modern-looking design. Expanding beyond the consumer market, touch sensing is beginning to take hold in medical, industrial and automotive applications for reasons such as aesthetics, maintenance, cost and cleanliness. Microchip enables engineers to add this leading-edge user interface to their designs, without the cost of fee-based licensing and royalty agreements. The Company's full source-code solution further enables design engineers to integrate touch sensing functionality with their existing application code in a single microcontroller, thus reducing the total system cost associated with current solutions.
Capacitive touch systems use parasitic capacitance to ground as a reference, and look for an increase in capacitance due to a touch by a user.
To employ capacitive touch systems you need a user interface, a sensor, a means for measuring the sensor's capacitance, and a means for validating when a capacitance shift is a touch by the user.
The mTouch system accomplishes this task by using the capacitance of the sensor as a frequency determining element in a relaxation oscillator. The frequency of the oscillator is then measured, and any shift due to a user's touch is detected and validated in software.