A touch sensor system includes a sensing area having a periphery and a plurality of light sources and a plurality of analog optical detectors arranged about the periphery of the sensing area. The system further includes addressing circuitry that selectively drives each of the plurality of light sources with a modulated signal and selectively activates the plurality of analog optical detectors, and a controller that receives a collective detector output from the plurality of analog optical detectors. The outputs from the analog optical detectors may be a time multiplexed to provide the collective detector output. Each optical detector may include a photodiode; a first transistor coupled to the photodiode in a current amplifier configuration that generates an amplified current output as a function of a photodiode current; and enable circuitry to enable and disable the optical detector as a function of an enable input signal.