ACS712 current sensor module with ESP32

Supply 5 V Bus ANALOG Measures current

Pins and ESP32 wiring

Pin	Role	ESP32 pin	Notes
VCC	Power	VIN	Needs 5 V: use VIN
OUT	Analog output	D34	Sits at 2.5 V with no current and can reach 5 V: use a voltage divider before the ADC
GND	Ground	GND
IP+	Not wired to the ESP32	—	Screw terminal: current path in. Never wire to the ESP32
IP-	Not wired to the ESP32	—	Screw terminal: current path out

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); }

void loop() {
  int mv = analogReadMilliVolts(34);  // OUT on GPIO 34
  Serial.println(mv);
  delay(200);
}

Allegro ACS712 datasheet, Output VCC/2 at zero current; sensitivity 185/100/66 mV per A (5/20/30 A versions)
Allegro ACS712 datasheet, Supply 4.5 to 5.5 V

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