A computer keyboard has a grid of conductors forming a plurality of
intersections, with force-sensitive resistor (FSR) elements located
between the conductors at the intersections. A plurality of keys are
located above the intersections and exert force on the conductors and FSR
elements during key presses. A resistor network sub-circuit is connected
to some of the conductors, and is switchable between low and high
resistance values. An Analog to Digital Converter (ADC) is coupled to the
resistor network sub-circuit. A microprocessor grounds a conductor and
tests another conductor for a threshold voltage level while the resistor
network is switched to the high resistance value. The microprocessor
switches the resistor network to the low resistance value upon detecting
the threshold voltage level and subsequently receives from the ADC a
digital value of a voltage on the tested conductor.