FRISTECH Inductive Proximity Sensors on Gravity Clock Pendulum

This is a precision falling ball gravity clock with a half-second pendulum. It uses a FTGCLK1 Control Board and two FRISTECH inductive proximity sensors. An output from the board drives the solenoid which lifts the ball after the pendulum impulse. The clock outputs are 3V AC to drive a modified quartz clock as a slave clock and / or selectable 12V AC or DC 24 ohm to drive one or more 30 second slave clocks. Another board with sensors is used with a one-second gravity clock. In both cases the time base is de