Simple Magnet Polarity Detector Circuit using Hall Effect Sensor

In many applications, such as motor control, magnetic field measurement, and instructional presentations, magnet polarity detection is essential.

This article explains how to use the APX9141 Hall Effect sensor to create a simple and reliable magnet polarity detector circuit.

The red and blue LEDs in the circuit represent the north and south poles of a magnet, respectively and offer visual feedback.

The circuit, which uses a CR2032 3V cell as power, is small and simple to put together, making it appropriate for both educational and hobbyist uses.

Circuit Working:

Parts List:

The APX9141 Hall Effect sensor is the key component of this circuit, which was built using a few readily accessible parts.

Its Hall element and two distinct outputs, DO and DOB, allow us to quickly identify the magnets poles.

The multifunctional APX9141 Hall Effect sensor finds the existence of a magnetic field.

In accordance to the magnetic fields intensity and polarity, it produces a voltage.

In this circuit, the polarity of the magnet determines which LED lights up as it gets close to the sensor:

In this circuit diagram, the North pole is represented by the Red LED linked to Pin 2 and the South pole by the Blue LED attached to Pin 3 of DOB.

Since this sensor can function at 3V, bias is provided by the CR2032 3V Cell.

The user may save battery life by turning the circuit on and off using a tactile switch.

Formulas:

The forward voltage drop between the LEDs is the subject of the following crucial formula in this circuit:

I = V_supply​ − V_LED​ / R_{internal​​}

where,

• I represents current through the LED
• Vsupply is the supply voltage 3V from the CR2032
• VLED is the forward voltage drop of the LED
• Rinternal​ is the Internal resistance of the battery

How to Build:

To build a Simple Magnet Polarity Detector Circuit using Hall Effect Sensor follow the below mentioned steps:

• Gather all the components mentioned in the above circuit diagram
• Connect IC APX9141 Hall Effect Sensor Vdd pin to CR2032 Battery 3V positive supply.
• Connect anode leg of Red LED to positive supply and cathode leg to DO pin of IC APX9141
• Connect anode leg of Blue LED to positive supply and cathode leg to DOB pin of IC APX9141
• Connect IC APX9141 Hall Effect Sensor GND pin to CR2032 Battery 3V negative supply through a tactile switch

Testing of Circuits

• Press the tactile switch to turn on the circuit after it has been built.
• Depending on the polarity of the magnet, place it in close proximity to the APX9141 and watch how the LED reacts.

Conclusion:

The APX9141 Hall Effect sensor magnet polarity detector circuit is a simple and effective method of seeing a magnets polarity.

This project, which requires few components, is ideal for novices and offers a useful application of the Hall Effect phenomena.

Through the circuits integration into other projects, users may investigate increasingly complex ideas related to magnetism and sensor technologies.

This circuit may be used as a useful tool in a variety of technical domains in addition to being instructional.

References:

Hall effect sensor