During the Spring semester of 2016, I built this continuously running pendulum as a demonstration piece for a dynamics class. The pendulum runs on either AA batteries or a solar panel. When running on the solar panel, it will charge the batteries and run for a couple of hours after the sun has set. The core of the circuit used to time the pendulum is a 555 timer IC chip, which, along with supporting capacitors and resistors, delays the pulse to the electromagnet until the pendulum is above the coil. The timer is triggered by a small reed switch and magnets located above the brass plumb bob used as a weight for the pendulum.