3144 Magnetic Field Detection Sensor

3144 Digital Magnetic Field Detection Sensor

Magnet Angle Motor Control A3144 A3144E OH3144 Y3144 Hall

     The 3144 is a Hall effect magnetic field sensor with digital output whose output changes when a magnet comes close. It comes in a small three lead TO-92S package and contains a Hall element, a comparator and an open collector output stage. When the south (S) pole of a magnet comes close enough to the marked face of the sensor the output goes LOW (0V); when the magnet moves away the output is released and goes HIGH through the pull-up resistor. It works between 4.5V and 24V, and up to 25mA can be drawn from its output.

     Magnetic reed switches also work well, but their glass bodies are fragile. Since the 3144 is fully in an IC package it is resistant to shocks, has no moving contacts and does not wear; with an output transition time of at most 2µs it can also detect fast rotating parts. With a small magnet fixed on a rotating shaft or wheel it is used for RPM and speed measurement, door and lid open detection, float level measurement and end position (endstop) detection. It has the same pinout and the same operating principle as sensors sold as A3144, A3144E, OH3144 and Y3144.

Key features:

     Contactless detection: It detects the magnet without touching it; since there is no contact there is no wear or contact bounce, and there is no glass body to break.

     Digital output: It gives a LOW output when the magnet is present and HIGH when it is absent; it is read directly by a digital input of the controller board with a pull-up resistor.

     Wide supply range: It works between 4.5V and 24V; it can be used in 5V circuits and in 12V / 24V systems without a separate regulator.

     Fast response: The output transition time of at most 2µs is suitable for counting revolutions of fast rotating shafts and wheels.

     Reverse supply protection: There is internal protection intended to protect the sensor when the supply leads are connected the wrong way round.

Features:

• Product type: Digital Hall effect magnetic field sensor (Hall switch)
• Model: 3144
• Equivalents: A3144, A3144E, OH3144, Y3144
• Detection: unipolar; south (S) pole approaching the marked face, non-latching
• Operating voltage: 4.5V - 24V (5V typical, absolute maximum 28V)
• Output type: open collector (NPN), pull-up resistor required
• Output behaviour: LOW (0V) when the magnet is present, HIGH when absent
• Output current: max 25mA
• Switching time: max 2µs
• Protection: reverse supply protection
• Compatible boards: Arduino, ESP32, ESP8266, STM32, Raspberry Pi and all controller boards with digital inputs (on 3.3V boards the sensor is supplied with 5V and the pull-up is connected to 3.3V)
• Pinout: with the marked face towards you, from the left 1 VCC, 2 GND, 3 OUT (DOUT)
• Package: TO-92S, 3 lead through hole
• Operating temperature: -40°C - +85°C
• Material and colour: black plastic IC body, "3144" printed on the body
• Dimensions: 4mm x 16mm
• Weight: 0.1gr

Usage information:

• With the marked face towards you, connect lead 1 (VCC) to 5V, lead 2 (GND) to GND and lead 3 (OUT) to a digital input of the controller board. Fit a 10K pull-up resistor between OUT and VCC (3.3V on 3.3V boards) or enable the internal pull-up of the board.
• Bring the south (S) pole of the magnet close to the marked face of the sensor; if the output goes LOW the correct pole is facing it. If the output does not change, turn the magnet over.
• For RPM measurement place the magnet on the rotating part and the sensor on the fixed part a few millimetres apart; one LOW pulse is counted per revolution.

Applications:

•  Motor and shaft RPM measurement
•  Bicycle and wheel speed measurement
•  Door and window open / closed detection
•  Float type liquid level measurement
•  3D printer and CNC endstop (end position) detection
•  Counting rotating parts and counter circuits
•  Robot wheel revolution counting (simple encoder)
•  Water meter and turbine flow measurement
•  Lid, drawer and cabinet open detection
•  Contactless limit switch applications

Precautions:

•  The output is open collector; without a pull-up resistor the output does not go HIGH and the value read is undefined.
•  The sensor responds to a south (S) pole facing its marked face; a north (N) pole held to the marked face does not change the output. If the magnet is on the back side the polarity is reversed and a north (N) pole triggers the output there.
•  This sensor does not measure the distance of the magnet or the field strength, it only gives a present / absent (digital) output; a linear Hall sensor (e.g. 49E) is needed for analog measurement.
•  Do not draw more than 25mA from the output; drive large loads such as relay coils through a transistor, not directly. The supply must not exceed 24V.
•  Do not bend the leads right at the body and do not heat them for long; keep soldering short.

Package contents:

•  1 pcs 3144 Magnetic Field Sensor
•  Note: magnet and pull-up resistor are not included in the package.