Hall Magnetic Sensor Module
A KY-003 Hall magnetic sensor module switches its digital output when the right magnetic field is nearby.
Part images
What it is
A KY-003 Hall magnetic sensor module switches its digital output when the right magnetic field is nearby.
How students use it
Students use it for door sensors, wheel magnets, contactless counters, and magnet-triggered projects.
Pins and power
Signal output, VCC, and GND on common KY-003 boards.
Use module power and output levels that are safe for Pico GPIO.
The digital output changes when the Hall sensor detects a field of the expected polarity/strength.
Voltage and safety
Confirm output level before connecting to Pico.
Keep strong magnets away from cards, drives, and medical devices.
Module internals
Main component: Digital Hall-effect switch.
Hall-effect sensor, support components, PCB, and header pins.
Datasheet notes
Digital Hall sensors are threshold devices, not continuous field-strength meters.
Common libraries
Use machine.Pin for the digital output.
Common mistakes
Using the wrong magnet pole, mounting too far away, expecting analog strength data, and forgetting shared ground.