Attributes

Brand	-
Category	Robotics / STEM Teaching Tools / Sensors
Origin	-
Model Number	KY-003
Sensor Type	Unipolar Hall Effect Switch
IC Chip	A3144E
Operating Voltage	4.5V to 24V DC
Output Type	Digital Open Collector
Operating Current	Typically 10mA
Pin Configuration	3-Pin (VCC, GND, OUT)
PCB Dimensions	15mm x 10mm
Mounting Hole	3mm Diameter
Application	Speed Detection, Position Sensing, Arduino Projects

6 reviews

Anonymous

Mar 21, 2026

Rating: 4/5

Good value, clear instructions needed

The sensor itself is high quality and detects magnets instantly. I deducted one star because there were no printed instructions included, but finding the pinout online was easy enough.

Anonymous

Mar 10, 2026

Rating: 5/5

Great for beginners

As someone new to electronics, this was very easy to wire up. Just three pins and it worked immediately. I'm using it to detect when a door closes in my smart home project.

Anonymous

Mar 10, 2026

Rating: 5/5

Reliable magnetic switch

I needed a lightweight solution for RPM monitoring on a drone propeller guard test rig. This little board is light, sturdy, and hasn't failed once after hundreds of cycles.

Anonymous

Mar 06, 2026

Rating: 5/5

Bulk buy success

Bought ten of these for our classroom kits. Every single one functioned perfectly out of the box. Students love seeing the LED light up when they bring a magnet close.

Anonymous

Mar 04, 2026

Rating: 4/5

Solid performance

Works exactly as described for a unipolar switch. It only triggers on one pole of the magnet, which is important to remember during installation. Good build quality for the price.

Anonymous

Mar 03, 2026

Rating: 5/5

Perfect for Arduino speed counters

This module works flawlessly with my Arduino Uno. I used it to build a tachometer for a small DC motor, and the response time is incredibly fast. The onboard LED indicator is a nice touch for debugging.

5 FAQ

Q: Can I use this directly to drive a relay?

A: No, the output current of this module is too low to drive a relay directly. You should use the output signal to trigger a transistor or a dedicated driver circuit that can handle the relay's current requirements.

Q: Does this module work with 3.3V logic levels like ESP32?

A: Yes, the A3144E operates down to 4.5V for power, but the output is open-collector. You can use it with 3.3V systems by powering the VCC at 5V and using a pull-up resistor to 3.3V on the output pin, or simply rely on the internal pull-up of your microcontroller if compatible.

Q: What is the maximum distance for magnet detection?

A: Detection distance depends heavily on the strength of the magnet used. With a standard neodymium magnet, it typically detects within 5mm to 10mm. Stronger magnets will increase this range slightly.

Q: Is this sensor bipolar or unipolar?

A: This is a unipolar Hall effect switch (A3144E). It activates only when a specific magnetic pole (usually South) approaches and remains on until the magnetic field drops below the release point.

Q: Does the package include magnets?

A: No, this package includes only the Hall Sensor Module board. Magnets are not included and must be sourced separately based on your specific project needs.

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