| Feature | Details |
| Sensor Type | Hall Effect (Unipolar) |
| Operating Voltage | 4.5V to 24V DC |
| Output Type | Open Collector (Requires Pull-up) |
| Magnetic Trigger | South Pole (Typically) |
| Package | TO-92 (Transistor-style) |
| Operating Temp | -40°C to +150°C |
Product Description The A3144 Hall Effect Sensor is a solid-state magnetic switch designed for non-contact sensing. Unlike mechanical switches or reed sensors, the A3144 has no moving parts, making it immune to mechanical wear and capable of extremely high-speed switching. When a magnetic field of sufficient strength (South Pole) is brought near the branded face of the sensor, the output transitions to a low voltage state. This makes it a favorite at Robogears for speedometers, brushless motor commutation, liquid level sensing, and limit switches in CNC or 3D printer machines.
Key Highlights
Solid-State Reliability: Because it uses the Hall Effect principle, it is vibration-resistant and has an almost infinite life cycle compared to mechanical reed switches.
High-Speed Operation: Capable of switching at frequencies in the kHz range, making it ideal for measuring the RPM of high-speed motors or turbines.
Wide Voltage Range: Operates reliably from 4.5V up to 24V, allowing it to interface directly with 5V microcontrollers like Arduino or 12V/24V industrial PLC systems.
Open Collector Output: The output is an "Open Collector," meaning you can easily interface it with different logic levels (3.3V or 5V) by using an external pull-up resistor.
Compact TO-92 Package: Its small, three-pin transistor shape allows for easy mounting in tight spaces or on custom PCBs.
Technical Specifications
Supply Current: 4.4mA to 9mA
Output Voltage (Low): 175mV to 400mV
Output Current: 25mA (Max)
Rise/Fall Time: 0.04μs / 0.18μs
Magnetic Threshold: ~350 Gauss (typical)
Installation Tip from Robogears Since the A3144 has an Open Collector output, you must use a pull-up resistor (typically 10kΩ) between the Output pin and VCC. Without this, the sensor will not show a high voltage when no magnet is present. If you are using an Arduino, you can simply use pinMode(pin, INPUT_PULLUP) in your code to use the internal resistor. Note that this is a Unipolar sensor; it only reacts to one pole of the magnet. If your sensor isn't triggering, try flipping the magnet over.
Note: This product is the A3144 Sensor ONLY. Magnets and resistors are sold separately. Product images are for illustration purposes only.