NAU7802 24-bit load cell ADC (I2C) with ESP32

Supply 3.3 V Bus I2C I2C address 0x2A Measures weight

Pins and ESP32 wiring

Pin	Role	ESP32 pin	Notes
3V3	Power	3V3	SparkFun Qwiic Scale-style order
GND	Ground	GND
SDA	I2C data (SDA)	D21
SCL	I2C clock (SCL)	D22
INT	Interrupt	D35	Data ready, optional
AVDD	Not wired to the ESP32	—	Analog supply output. Leave unconnected
RED	Not wired to the ESP32	—	Load cell E+
BLK	Not wired to the ESP32	—	Load cell E-
WHT	Not wired to the ESP32	—	Load cell A-
GRN	Not wired to the ESP32	—	Load cell A+
YLW	Not wired to the ESP32	—	Load cell shield, optional

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

Starter code (Arduino)

#include <Wire.h>

void setup() {
  Serial.begin(115200);
  Wire.begin(21, 22);  // SDA = GPIO 21, SCL = GPIO 22
  Wire.beginTransmission(0x2A);
  bool found = Wire.endTransmission() == 0;
  Serial.println(found ? "NAU7802 24-bit load cell ADC (I2C) found at 0x2A" : "Not found: check power, GND and SDA/SCL");
}

void loop() {}

Sources

Nuvoton NAU7802 datasheet, Fixed I2C address 0x2A; 24-bit ADC with PGA for bridge sensors

Try it in 3D in BoardPilot

BoardPilot Part data (JSON)

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

NAU7802 24-bit load cell ADC (I2C) with ESP32

Pins and ESP32 wiring

Starter code (Arduino)

Sources

Try it in 3D in BoardPilot

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