Synaptics' proven capacitive sensing technology can also be applied to force sensors. In a capacitive force sensor, two metal plates, separated by a small air gap, are positioned close together. Force applied on one of the plates changes the capacitance between them. Synaptics has developed a capacitive force sensing technology suitable for applications as diverse as pointing sticks, vacuum gauges, and high-resolution pressure sensors.

How the Capacitive Force Sensing Works

Our TouchStyk is a pointing stick built using our capacitive force sensing technology. Like other pointing sticks, the TouchStyk senses the force of the finger applied to a small rubber cap. Where other pointing sticks use less reliable strain gauges to measure the applied force, the TouchStyk measures force capacitively. The rubber cap of the TouchStyk is connected to a metal plate mounted above a Synaptics capacitive sensor (figure 1).

Figure 1