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Lesson 06: Hall Sensor Module

In this lesson, you will learn how to use a Hall sensor with an ESP32 Development Board to detect the polarity of a magnetic field. We’ll cover reading analog signals from the sensor and interpreting them to differentiate between south and north poles. This project is ideal for beginners in electronics, providing practical experience with sensors and signal processing on the ESP32 platform.

Required Components

In this project, we need the following components.

It’s definitely convenient to buy a whole kit, here’s the link:

Name	ITEMS IN THIS KIT	LINK
Universal Maker Sensor Kit	94	Universal Maker Sensor Kit

You can also buy them separately from the links below.

Component Introduction	Purchase Link
ESP32 & Development Board (ESP32 Board)	BUY
Hall Sensor Module	-
Breadboard	BUY

Wiring

../_images/Lesson_06_Hall_Sensor_Module_esp32_bb.png

Code

Code Analysis

Setting up the Hall Sensor
```
const int hallSensorPin = 25;  // Pin connected to the Hall sensor output
void setup() {
  Serial.begin(9600);             // Initialize serial communication at 9600 bps
  pinMode(hallSensorPin, INPUT);  // Set hall sensor pin as input
}
```
The hall sensor’s output is connected to pin 25 on the ESP32 Development Board. The setup() function is used to initialize serial communication at 9600 bits per second (bps) for displaying data on the serial monitor. The pinMode() function is used to configure 25 as an input pin.

Reading from the Hall Sensor and Determining Polarity

The Hall sensor module is equipped with a 49E linear Hall effect sensor, which can measure the polarity of the magnetic field’s north and south poles as well as the relative strength of the magnetic field. If you place a magnet’s south pole near the side marked with 49E (the side with text engraved on it), the value read by the code will increase linearly in proportion to the applied magnetic field strength. Conversely, if you place a north pole near this side, the value read by the code will decrease linearly in proportion to that magnetic field strength. For more details, please refer to Hall Sensor Module.

void loop() {
  int sensorValue = analogRead(hallSensorPin);  // Read analog value from Hall sensor
  Serial.print(sensorValue);                    // Output raw sensor value to Serial Monitor
  delay(200);                                   // Delay for 200 milliseconds

  // Determine magnetic pole based on sensor value
  if (sensorValue >= 2600) {
    Serial.print(" - South pole detected");  // South pole detected if value >= 2600
  } else if (sensorValue <= 1200) {
    Serial.print(" - North pole detected");  // North pole detected if value <= 1200
  }

  Serial.println();  // New line for next output
}