7Semi NAU7802 – 24-bit Load Cell ADC Library

7Semi_NAU7802 is an Arduino-compatible library for the NAU7802 24-bit low-noise ADC, commonly used in load cell and weighing scale applications.

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Features

• 24-bit signed ADC reading (high resolution)
• I2C interface (Arduino / ESP compatible)
• Programmable Gain Amplifier (PGA 1–128)
• Internal LDO voltage configuration
• Selectable conversion rates
• Raw ADC read and averaged read
• Tare (zero) functionality
• Scale calibration using known weight
• Weight output in user-defined units
• User-friendly examples with Serial prompts
• ESP32 / ESP8266 custom SDA/SCL support

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Supported Platforms

• Arduino Uno / Nano / Mega
• ESP32
• ESP8266
• Any Arduino-compatible board with I2C support

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Installation

Arduino Library Manager

1. Open Arduino IDE
2. Go to Sketch → Include Library → Manage Libraries
3. Search for 7Semi_NAU7802
4. Click Install

Manual Installation

1. Download this repository as ZIP
2. Extract into your Arduino libraries folder
3. Restart Arduino IDE

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Hardware Connections

NAU7802 Module → MCU

NAU7802 Pin	MCU Pin
VCC	3.3V (recommended)
GND	GND
SDA	SDA
SCL	SCL

⚠️ Some NAU7802 modules support 5V. Always check your module datasheet.

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Load Cell (4-wire) Connections

Most common color code:

Load Cell Wire	NAU7802 Pin
Red	E+ (Excitation +) AVDD
Black	E- (Excitation -) GND
Green	A+ (Signal +)
White	A- (Signal -)

Important Notes:

• Wire colors are common but not universal
• Always verify with the load cell datasheet
• If weight is inverted, swap A+ and A-

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Basic Usage Flow

1. Initialize sensor using begin()
2. Configure LDO and PGA
3. Tare with empty platform
4. Calibrate using known weight
5. Read weight continuously

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