Description
Reviews
| 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 |
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.
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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