Attributes

Brand	-
Category	Robotics / STEM Teaching Tools / Sensors
Origin	-
Model Number	KY-003
Sensor Type	A3144E Unipolar Hall Effect
Operating Voltage	4.5V to 24V DC
Output Signal	Digital Switch (Low when magnetic field detected)
Pin Configuration	3-Pin (GND, VCC, Signal)
PCB Dimensions	18mm x 13mm x 3mm
Mounting Hole Diameter	3mm
Response Time	< 4 microseconds
Operating Temperature	-40°C to +85°C
Compatibility	Arduino, Raspberry Pi, ESP32, STM32

6 reviews

Anonymous

Mar 31, 2026

Rating: 5/5

Great for beginners

Plug and play with most microcontroller boards. The built-in pull-up resistor saves time on prototyping. Excellent quality for the price point.

Anonymous

Mar 21, 2026

Rating: 5/5

Perfect for RPM counting projects

I used this module to build a tachometer for my 3D printer fan. The response is instant and the output is clean. Very easy to interface with an Arduino Uno.

Anonymous

Mar 16, 2026

Rating: 5/5

Essential component for robotics

Bought five of these for a line-following robot project using magnetic tape. They are consistent and robust. Highly recommended for students and makers.

Anonymous

Mar 16, 2026

Rating: 4/5

Solid performance

Works well within the specified voltage range. I tested it at 5V and 12V with no issues. Just remember it's unipolar, so it only reacts to one pole of the magnet.

Anonymous

Mar 11, 2026

Rating: 5/5

Reliable and compact

Small footprint makes it easy to fit into tight enclosures. I'm using it as a door open/close detector for a smart home project. No false triggers so far.

Anonymous

Mar 03, 2026

Rating: 4/5

Good value, works as expected

The sensor triggers reliably with a standard neodymium magnet. The only minor issue is that the silk screen on the PCB is slightly faint, but the pinout is standard so it wasn't a big problem.

5 FAQ

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

A: Yes, the module operates between 4.5V and 24V for power, but the digital output is compatible with 3.3V logic systems. Many users successfully connect it directly to ESP32 GPIO pins.

Q: Which magnetic pole triggers the sensor?

A: The A3144E is a unipolar switch. Typically, the South pole of a magnet facing the front of the sensor (the side with the chip) will trigger the output to go Low. Please test with your specific magnet orientation.

Q: What is the maximum current this sensor can switch?

A: This module is designed for signal processing, not high-power switching. The output current is limited (typically around 25mA). You should use a transistor or relay to drive higher loads like motors or bright lamps.

Q: Can I use this underwater?

A: The PCB itself is not waterproof or conformal coated. If you need to use it in wet environments, you must enclose the entire module in a waterproof housing while ensuring the magnet can still affect the sensor through the casing.

Q: Is there a built-in LED indicator on the board?

A: Yes, there is a small SMD LED on the module that lights up when the magnetic field is detected and the output switches to Low, providing visual feedback.

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