It’s an electromagnet pendulum analog circuit. Whether you’re building it, or just studying the schematics, this is a fun way to brush up on the non-digital side of the craft. The pendulum is ...

For more, watch [Josh] describe his method in person after the break, or try flashing his code to an Arduino and make a waving cat of your own.

Remember - these variables are controlled (or kept the same) because to make it a fair test ... the magnetic field and hence the stronger the electromagnet. Hazard Consequence Control measures ...