HX711 AD Module – 24-Bit Precision Weighing Sensor for Arduino, Electronic Scale & Pressure Measurement (UART Serial Output)

Description

The HX711 AD Module is a precision 24-bit analog-to-digital converter (ADC) designed specifically for weighing scales and industrial control applications. It interfaces directly with bridge sensors such as load cells, strain gauges, and pressure sensors, converting the tiny millivolt-level analog output into a high-resolution digital signal for microcontrollers .

The module is built around the Avia Semiconductor HX711 IC, which integrates a low-noise programmable gain amplifier (PGA), an on-chip oscillator, and a regulated power supply for the load cell. The PGA offers selectable gains of 32, 64, and 128—Channel A supports gain 64/128, while Channel B supports gain 32 . The board communicates via a two-wire interface (DAT and CLK), requiring no special protocol or library for basic operation . The module supports selectable 10Hz or 80Hz output data rates, with 10Hz offering better noise rejection for stable readings and 80Hz suitable for faster, dynamic measurements . It operates from a 2.6V to 5.5V supply and draws less than 1.5mA during normal operation .

Critical limitations: The HX711 is an ADC, not a complete scale. It requires a load cell (separate component) and calibration to convert raw readings to meaningful weight units. The 2-wire interface is not standard UART or SPI—it uses a bit-banged protocol where clock pulse counts select the gain/channel . Power supply noise directly affects measurement stability—a clean, regulated supply with proper decoupling is essential. For 3.3V logic systems, note that many modules have an internal regulator outputting ~4.29V for load cell excitation, which can cause issues with 3.3V microcontrollers .

Features

• 24-Bit High-Resolution ADC: Designed specifically for weigh scales and bridge sensors .

• Selectable Gain (32/64/128): On-chip low-noise PGA adapts to different load cell sensitivities .

• Two-Wire Interface (DAT/CLK): Simple connection to any microcontroller GPIO .

• Selectable Output Data Rate: 10Hz (stable) or 80Hz (faster) via onboard jumper .

• On-Chip Regulator: Provides clean power for the load cell and ADC analog supply .

• Simultaneous 50/60Hz Rejection: Reduces mains interference for stable readings .

• Wide Supply Range (2.6V–5.5V): Compatible with both 3.3V and 5V systems .

• Compact PCB with Terminal Block: Easier wiring and secure connections for load cells.

Technical Specifications