Magnetic, Hall & Angle Sensors

Magnetic sensors detect magnets. That makes them good for measuring position and rotation, counting wheel turns, and noticing when a door or lid opens.

  • A Hall effect sensor switches or changes its output when a magnet comes close. It is used in speedometers, contactless switches and position detectors.
  • A reed switch, or a ready-made magnetic door sensor such as the MC-38, closes when a magnet is near. It is the simplest way to know whether a door, fridge, letterbox or pill-box lid is open.
  • The AS5600 goes further. It reads the angle of a magnet spinning above it as a 12-bit value over I2C (address 0x36), so you can measure knob position or motor angle without contact.

How to choose:

  • Pick a reed or door sensor for open/closed.
  • Pick a Hall sensor for counting or proximity.
  • Pick an AS5600 for precise angle.

All of these work with Arduino and ESP32. The AS5600 wires to SDA and SCL. On an ESP32, use GPIO21 and GPIO22, and tie DIR to GND to set the direction.

Magnet strength and distance matter. Test with your real magnet before fixing the mounting.

Frequently asked questions

Hall sensor or reed switch?

Either detects a magnet. A Hall sensor is solid-state and suits fast counting; a reed switch is simplest for open/closed.

How does the AS5600 measure angle?

It reads the direction of a magnet spinning above the chip and reports a 12-bit angle over I2C.

What address does the AS5600 use?

0x36.

How do I detect a door opening?

Use a magnetic door sensor (reed switch). It changes state when the magnet moves away.

Guides

Reference pages on soldr.ai

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