How to connect my hall effect sensors to my microcontroller?

Connecting Hall effect sensors to your microcontroller (MCU) is straightforward, but depends on whether you're using a digital or analog Hall sensor.

Step 1: Determine Your Sensor Type

Step 2: Wiring Diagram
Digital Hall Effect Sensor (e.g., A3144)
Pins:

• Vcc: Connect to 3.3V or 5V (check sensor datasheet)
• GND: Ground
• OUT: Connect to digital GPIO input

Circuit:

• Add a pull-up resistor (~10kΩ) between OUT and Vcc (if not already onboard).
• OUT will go LOW when a magnet is detected, HIGH otherwise.

plaintext

[ A3144 Sensor ]
 Vcc --- 3.3V or 5V
 GND --- GND
 OUT --- GPIO (with 10kΩ pull-up to Vcc)

MCU Code (Polling Example in C):

c

if (HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_0) == GPIO_PIN_RESET) {
    // Magnet detected
}

Analog Hall Sensor (e.g., SS49E)
Pins:

• Vcc: 3.3V or 5V
• GND: Ground
• OUT: Analog voltage (connect to ADC pin)

Circuit:

• No pull-up needed.
• Output voltage is typically mid-scale (e.g., ~2.5V) when no magnetic field is present.
• Varies higher or lower depending on magnetic field direction and strength.

plaintext

[ SS49E Sensor ]
 Vcc --- 3.3V or 5V
 GND --- GND
 OUT --- ADC pin (e.g., PA0)

MCU Code (STM32 ADC Example):

c

uint32_t adc_val = HAL_ADC_GetValue(&hadc1);
// Convert to voltage
float voltage = (adc_val * 3.3) / 4095.0;

Step 3: Setup in STM32CubeMX (If using STM32)

• Digital Sensor: Configure GPIO as input, optionally with interrupt.
• Analog Sensor: Enable ADC, select correct pin, and configure sampling time.

Tips

• Check your Hall sensor's operating voltage before connecting to a 3.3V or 5V MCU.
• Use decoupling capacitors (0.1µF) near the sensor for noise filtering.
• For multiple sensors, assign each to a separate GPIO or ADC channel.
• Use interrupts for real-time edge detection with digital sensors.