Close switch to start oscillator. Two electromagnets get powered by PWM. Adjust the left hand pot to change the duty cycle going into each electromagnet.
An iron pin is placed between the electromagnets on a linear slide, and gets attracted to whichever coil has the strongest magnetic field. The pot has direct control over the position of the pin.
got this idea from a tiny rc car I pulled apart. It has two coils and a slide and a tiny magnet between the coils. the coils are plugged into a H-bridge which only outputs dc +3v, 0v, or -3v. This makes the car unsteerable; there's no centre hold or proportional steering control, so the wheels can only full lock left or right, or just flap about uselessly.
