Physics 427

Dr. Ayars

Magnetic Levitation

Build and/or program a Proportional Integral Differential (PID) controller to maintain the height of a steel ball bearing below an electromagnetic coil. This one is considerably more difficult than levitating a ping-pong ball in a tube, but it's also way cooler.

The apparatus was built by Eric Ayars, starting with a design used in the Advanced Lab at UC Berkeley. It has been done successfully twice so far: once using an op-amp circuit (Dr. Ayars) and once using a Teensy 3.1 microcontroller (Charris Gabaldon and Robert Keen, 2016.) Note that it does not work with an Arduino (the Arduino PWM frequency is too low.) Whether it's possible with a LabVIEW program is still an open question.

Regardless of the control mechanism used, you'll have to build your own photodiode amplifier circuit. Refer to your PHYS 327 notes, or to Dr. Ayars.

Reading

Location

Room 108, cabinet 108.24.

Additional equipment needed

Cautions

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