Magnetic Levitation: Ferrite and Neodymium Magnets

Introduction to Magnets

• Permanent Magnets: Ferrite and neodymium magnets have two magnetic poles: north and south, which create magnetic fields.
• Forces between Magnets:
  • Same magnetic polarity: Creates a repulsive force.
  • Opposite magnetic polarity: Creates an attractive force.
• Magnetic levitation occurs when a repulsive force counteracts the weight of an object.

Earnshaw's Theorem

• States that there is no equilibrium position in static electric or magnetic fields.
• Challenges the possibility of stable magnetic suspension.

Experiment and Challenges

• Attempting to levitate a magnet by positioning one above another with same polarities results in temporary suspension.
• The suspension only lasts milliseconds due to lack of stability as per Earnshaw's Theorem.

Solution with Electromagnets

• Electromagnet Introduction:
  • Created by applying voltage to a metal cylinder with wires, generating a magnetic field when powered.
  • Unlike permanent magnets, its magnetic field is not static and can be controlled.

Feedback and Control System

• Closed-loop feedback system:
  • Required to stabilize the magnetic levitation.
  • Uses an electromagnet placed above permanent magnets.

Hall Effect Sensor

• SS 495 Linear Hall Effect Sensor:
  • Detects magnetic field changes.
  • Voltage output decreases or increases from 2.5 volts based on magnet polarity.
  • Positioned under magnets to control electromagnet based on voltage changes.

Circuit Implementation

• Comparator Circuit:
  • Utilizes an LM 393 comparator.
  • Controls electromagnet based on Hall sensor voltage output.
• MOSFET Driver:
  • Turns electromagnet on/off in response to Hall effect signal.

Enclosure and Build

• Constructed using acrylic glass.
• Design allows adjustment of electromagnet height.

Problem Encountered

• Difficulty achieving stable levitation.
• Comparator circuit not optimal; threshold values for turning on/off electromagnet are too far apart.

Conclusion and Future Work

• Current prototype offers basic magnetic levitation.
• Further refinement needed; comparator circuits need optimization.
• Future exploration: Commercial products usually place electromagnets differently.

Final Remarks

• Encouragement to explore and stay creative.
• Reminder to engage with content by liking, sharing, and subscribing.