  The PANOSETI experiment is an all-sky, all-the-time visible search for
nanosecond to millisecond time-scale transients. The experiment will deploy
observatory domes at several sites, each dome containing ~45 telescopes and
covering ~4,440 square degrees. Here we describe the focal-plane electronics
for the visible wavelength telescopes, each of which contains a Mother Board
and four Quadrant Boards. On each quadrant board, 256 silicon photomultiplier
(SiPM) photon detectors are arranged to measure pulse heights to search for
nanosecond time-scale pulses. To simultaneously examine pulse widths over a
large range of time scales (nanoseconds to milliseconds), the instrument
implements both a Continuous Imaging Mode (CI-Mode) and a Pulse Height Mode
(PH-Mode). Precise timing is implemented in the gateware with the White Rabbit
protocol.
