Introduction: Magnetic Pendulum ( With Hall Effect Sensor )

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About: Music: my profession for over 40 years... Electronics: my beloved hobby always.

Build this simple Magnetic Pendulum with very few components. Hall effect sensor is used to detect the presence of magnetic field, and "push" the pendulum in the exact moment. Electromagnet is "ON" during only 20mS and battery power drain is low.

Step 1: Images of Device - Watch Video on Last Step.

Step 2: Phase 1

Step 3: Phase 2

Step 4: Phase 3

Step 5: Circuit & Main Components

Hall sensor: UGN-3503-U

IC1: LM358N( dual OP amp )

IC2: CD4001(quad cmos nor gate )

FET1: IRFD-120( n-channel power mosfet )

Step 6: Hall Sensor Operation

Step 7: Direction Detector

IC1 output will be low when pendulum is approaching it. It will be high when it is moving away.

Step 8: Monostable

when IC1 out is high, monostable IC2 will trigger with a 20mS output pulse.

Step 9: Driving FET

pulse from IC2 biases mosfet gate and electromagnet L1 conducts pushing pendulum. It also drives LED on.

Step 10: Voltage Drop

diode D1 drops 6V from battery to around 5.3v ( optimum voltage ) . Hall sensor will break down above 6v.

Step 11: The Electromagnet

Step 12: For More Details & Images Watch Video. Thank You!