Description
Reviews
| Brand | - |
| Category | Robotics / STEM Teaching Tools / Sensors |
| Origin | - |
| Model Number | KY-003 / A3144E |
| Operating Voltage | 4.5V to 24V DC |
| Output Type | Digital Switch (Open Collector) |
| Sensing Principle | Unipolar Hall Effect |
| Pin Configuration | 3-Pin (GND, VCC, Signal) |
| LED Indicator | Yes, Power On/Signal Status |
| Mounting Hole Diameter | 3mm |
| PCB Dimensions | 16mm x 12mm x 3mm |
| Compatible Platforms | Arduino, Raspberry Pi, ESP32 |
| Application Range | Speed Detection, Position Sensing, Proximity Switching |
Anonymous
Mar 24, 2026
Rating: 5/5
Perfect for Arduino projects
This module works flawlessly with my Arduino Uno. The detection range is consistent, and the built-in LED makes debugging very easy. Great value for the price.
Anonymous
Mar 14, 2026
Rating: 5/5
Reliable magnetic switch
Used this to create a non-contact limit switch for my 3D printer modification. It has been running for weeks without any false triggers. Highly recommended.
Anonymous
Mar 14, 2026
Rating: 5/5
Fast shipping and works great
Arrived earlier than expected. Tested immediately with a simple sketch and the output signal is crisp. No noise issues observed even with long wires.
Anonymous
Mar 10, 2026
Rating: 4/5
Solid build quality
The PCB looks clean and the soldering points are well-made. It detects standard neodymium magnets from about 1cm away, which is perfect for our conveyor belt counter.
Anonymous
Mar 10, 2026
Rating: 5/5
Great for learning electronics
Bought a pack of five for my university project. All of them worked out of the box. The voltage range is wide enough for both 5V and 12V systems.
Anonymous
Mar 06, 2026
Rating: 4/5
Good sensor, clear documentation needed
The hardware quality is solid and responds quickly to magnets. I deducted one star because the pinout wasn't clearly marked on the back, but a quick multimeter check solved it.
Q: Can I use this outdoors in the rain?
A: The PCB itself is not waterproof or conformal coated. If you plan to use it outdoors, you must enclose it in a waterproof housing or apply your own conformal coating to protect the electronics from moisture.
Q: Is this a bipolar or unipolar sensor?
A: This is a unipolar Hall effect sensor. It activates when a magnetic south pole approaches the front face of the package and deactivates when the magnet is removed. It does not require a north pole to reset.
Q: What is the maximum current this sensor can switch directly?
A: The A3144E chip itself has a limited output current capability (typically around 25mA). It is designed to drive logic inputs or small LEDs. For driving motors or relays, please use an external transistor or MOSFET.
Q: How far away can it detect a standard fridge magnet?
A: Detection distance depends on the strength of the magnet. For a standard ceramic fridge magnet, the range is typically 5mm to 10mm. Stronger neodymium magnets can be detected from 15mm to 20mm away.
Q: Does this module work with 3.3V logic levels like the ESP32?
A: Yes, the module operates between 4.5V and 24V, but the output is open-collector. You can use it with 3.3V systems by powering the module at 5V and using a pull-up resistor to 3.3V on the signal line, or simply rely on the low-state grounding which is compatible.
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