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There are plenty of clock projects documented online. This one differs in that timekeeping is controlled by a magnetically driven free pendulum.

A free pendulum has no mechanical linkage, escapement mechanism or direct mechanical power to keep it going. A small magnet on the bottom of the pendulum induces a voltage on a coil mounted beneath as it swings past. The voltage is detected by Teensy's a/d converter and triggers a propulsion pulse applied to the coil from a digital output pin. This gives the pendulum a tiny nudge to keep it going. The pendulum defies the senses, swinging in eerie silence.

A Teensy performs all electronic functions—only a couple passive components added. A setup mode measures the pendulum timing using the processor clock as a reference to allow quick pendulum adjustments. Digital outputs can drive two types of modified analog clock movements—the click-click one-second advancing type and the newer silent, continuous motion type.