Touch sensing is fast becoming an alternative to traditional pushbutton switch user interfaces, because it requires no mechanical movement, and it 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. Cypress PSOC, provides a free and easy method for designers to add touch sensing to applications utilizing their microcontrollers without the cost of fee-based licensing and royalty agreements. Being a source-code solution further helps engineers quickly integrate touch sensing functionality with their existing application code in a single, standard microcontroller, thus reducing the total system cost associated with current solutions.

Capactive Switch basically is a pair of adjacent plates (please refers below figure). Small edge to edge capacitance is present, the intent

of the switch layout is to minimize the capacitance between these plates. When a conductive object like figure is placed in proximity to the

two plates, (refer fig. B), there is a capacitance between one electrode and the conductive object and a similar capacitance between the

conductive object and the other electrode.

The most common form of capacitance switch array is a set of capacitors where one side of each is grounded. Thus the active capacitor has

only one accessible side; the switch is grounded variable capacitor.The presence of the conductive object increases the capacitance of the

switch to ground. The switch action is determined by measuring the change in the capacitance.

Capsense technology can be applied to varies applications, such as …