HX711 Load Cell Amplifier Module 24-Bit ADC for Weight Sensors

Quick Introduction: If you want to build a digital scale, a smart inventory shelf, or a force-feedback joystick, you need to measure the tiny changes in resistance from a load cell. Microcontrollers cannot read these microvolt-level signals directly. Enter the HX711 Amplifier Module. This specialised 24-bit Analogue-to-Digital Converter (ADC) amplifies the faint signal from your load cell and converts it into a digital value that your Arduino, ESP32, or Raspberry Pi can easily read.

Detailed Specifications

• Main Chip: HX711.

• Resolution: 24-Bit (High Precision).

• Channels: 2 (Channel A & Channel B).

• Selectable Gain:

  • Channel A: 128 or 64.

  • Channel B: Fixed 32 (System monitoring).

• Input Voltage: 2.6V to 5.5V DC.

• Data Output Rate: 10Hz (Default) or 80Hz (Selectable via solder jumper).

• Interface: Two-wire serial (Clock & Data) - Not I2C, but simple GPIO bit-banging.

• Operating Current: < 1.5mA (Normal), < 1uA (Power Down).

Quality Advantage & Differentiation: Why use this Probots HX711 module?

1. Stable Layout: Designed with proper ground planes to minimise noise interference, which is critical when measuring voltage changes in the nanovolt range.

2. Breadboard Friendly: Standard 2.54mm pitch headers make it easy to plug into breadboards or solder into perfboards.

3. Wide Compatibility: Works seamlessly with 3.3V logic (ESP32/Raspberry Pi) and 5V logic (Arduino Uno/Mega) without external level shifters.

Key Applications & Usage

• Digital Weighing Scales: From kitchen scales to heavy industrial platform scales.

• Smart Inventory: Detect when an item is removed from a shelf.

• Force Measurement: Measure the thrust of a rocket motor or the grip strength of a robotic hand.

• Centre of Gravity: Use 4 load cells (one on each corner) to calculate the CoG of an object.

What's Included & Required

• Included: 1x HX711 Load Cell Amplifier Module PCB.

• Required:

  • Resistive Load Cell (4-wire).

  • Microcontroller (Arduino/ESP/Pi).

  • Jumper Wires.

The "Virtual Technician" Support Panel

• ⚠️ CRITICAL SETUP TIP: 10Hz vs 80Hz

  • Default Mode (10Hz): The chip comes configured for 10 samples per second. This is slow but offers maximum stability and noise rejection. Great for static scales.

  • High Speed (80Hz): If you need a faster response (e.g., for balancing robots or dynamic force measurement), you must locate the solder jumper marked "RATE" or pin 15 on the chip and connect it to VCC. Note: Precision drops slightly at 80Hz.

• ⚠️ WIRING GUIDE (Standard Load Cell):

  • • Microcontroller Side:

      • VCC -> 3.3V or 5V

      • GND -> GND

      • DT (Data) -> Any Digital GPIO

      • SCK (Clock) -> Any Digital GPIO

    • Sensor Side: Follow the E+/E-/A+/A- color code (Red/Blk/Wht/Grn usually).

• Mechanical Assembly Tip:

  • Mounting: Use nylon standoffs to keep the PCB off conductive surfaces.

  • Vibration: Mount the module away from the vibrating parts of your machine to avoid microphonic noise in the capacitors.

• Troubleshooting: Reading Drift?

  • HX711 is sensitive to temperature and power supply noise.

1. 1. 1. Use a stable power source (not a noisy USB).
      2. Twist your load cell wires to create a twisted pair shield.
      3. Keep wires as short as possible.

Helpful Tutorials & Resources

• • 1. Datasheet:

    • Download PDF

  • 2. Library:

    • Link: Access Repository