Hall Effect Sensors

1. Definition

A Hall Effect Sensor detects magnetic fields and converts them into an electrical signal.
It works on the Hall Effect principle, where a voltage is generated when a magnetic field passes through a conductor or semiconductor.

These sensors are used for speed detection (in fans, wheels), position sensing, proximity sensing, and even in brushless DC motors.

hall effect sensor module

Hall Effect Sensor Symbol

hall effect symbol

2. Features

  • Magnetic Field Detection: Can sense the presence, strength, or direction of a magnetic field.
  • Contactless Sensing: No physical contact needed, reduces wear and tear.
  • High Reliability: Works in dusty, dirty, or wet environments where mechanical switches might fail.
  • Types:
    • Analog: Output changes smoothly with magnetic field strength.
    • Digital: Output is either ON or OFF depending on magnetic field detection.
  • Non-Polarized Sensing Face: Detects magnets from either pole (some sensors are pole-specific).

4. How to Use

4.1. Identify the Pins (e.g., A3144 Hall Sensor)

  • VCC: Connect to 5V or 3.3V (check datasheet).
  • GND: Ground connection.
  • OUT: Signal output pin.

hall effect sensor pins

4.2. Choose the Right Type

  • Digital Hall Sensor: For detecting if a magnet is present or not (e.g., A3144).
  • Analog Hall Sensor: For measuring magnetic field strength (e.g., SS49E).
  • Latching Hall Sensor: Turns ON with one pole, OFF with the opposite pole, good for rotation tracking.

4.3. Connect It Correctly

  • To Arduino:
    • VCC → 5V
    • GND → GND
    • OUT → Any digital pin (digital sensor) or analog pin (analog sensor)
  • Place the sensor so the flat face points toward the magnet.
  • Keep wiring short for cleaner signals.

4.4. Test It

  • For digital sensors:
    • Bring a magnet close → output goes LOW (or HIGH depending on type).
    • Remove the magnet → output returns to normal.
  • For analog sensors:
    • Read the voltage from the OUT pin.
    • Voltage changes as magnet moves closer or farther.
  • Use Arduino’s Serial Monitor to see the readings in real time.

4.5. Mount Securely

  • On breadboard: Use jumper wires for quick testing.
  • In projects: Fix with glue, screws, or brackets so it stays aligned with the magnet.
  • Avoid placing it near strong stray magnetic fields unless they are part of your measurement.

Tip: Hall sensors won’t detect non-magnetic materials like plastic, wood, or aluminum, they only react to magnets.

5. Video Explanation

video coming soon