A3144 hall effect switch with ESP32

Supply 5 V Bus GPIO Measures magnetic field

Pins and ESP32 wiring

Pin	Role	ESP32 pin	Notes
VCC	Power	VIN	Left leg, printed face towards you. Needs at least 4.5 V: use VIN
GND	Ground	GND	Middle leg
OUT	Output (the part drives it)	D25	Right leg. Open collector: use INPUT_PULLUP (to 3.3 V), never a pull-up to 5 V

Suggested wiring for the 30-pin ESP32 DevKit, avoiding flash, input-only and strapping pins. BoardPilot checks it for you as you wire.

This module is sold for 5 V. Its outputs may be 5 V: use a level shifter or a voltage divider on ESP32 inputs.

void setup() {
  Serial.begin(115200);
  pinMode(25, INPUT);  // OUT
}

void loop() {
  Serial.println(digitalRead(25));
  delay(100);
}

Allegro A3141/2/3/4 datasheet, Pin 1 supply, 2 ground, 3 output (open collector); supply 4.5 to 24 V

Part data: CC BY 4.0, free to reuse with credit to BoardPilot.