How to Use HX711 4 digit Display Electronic Scale Pressure Module: Examples, Pinouts, and Specs

The HX711 4-Digit Display Electronic Scale Pressure Module is a versatile and cost-effective component designed for weight measurement applications. It integrates the HX711 precision 24-bit analog-to-digital converter (ADC) with a 4-digit 7-segment display, making it ideal for building electronic scales, pressure measurement systems, and other load cell-based applications. This module simplifies the process of interfacing load cells with microcontrollers, providing accurate and stable readings.

• Digital weighing scales
• Pressure measurement systems
• DIY weight measurement projects
• Industrial load monitoring
• Educational and prototyping purposes

1. Power the Module: Connect the VCC pin to a 5V DC power source and the GND pin to ground.
2. Connect the Load Cell: Attach the load cell wires to the E+, E-, A+, and A- pins. Ensure proper polarity and secure connections.
3. Interface with Microcontroller:
   • Connect the DT and SCK pins of the HX711 to the corresponding GPIO pins on your microcontroller.
   • Connect the DIO and CLK pins of the 4-digit display to separate GPIO pins.
4. Write Code: Use a microcontroller (e.g., Arduino UNO) to read data from the HX711 and display it on the 4-digit display.

• Load Cell Calibration: Calibrate the load cell to ensure accurate weight measurements. This involves determining the scale factor and offset.
• Stable Power Supply: Use a stable 5V power source to avoid fluctuations in readings.
• Noise Reduction: Place the module away from high-frequency noise sources and use shielded cables for the load cell.
• Mounting: Securely mount the load cell to prevent mechanical vibrations or misalignment.

Below is an example Arduino sketch to interface the HX711 module and display weight on the 4-digit display.

#include "HX711.h" // Include HX711 library for ADC communication
#include "TM1637Display.h" // Include TM1637 library for 4-digit display

// Pin definitions for HX711
#define DT_PIN 3  // Data pin connected to HX711 DT
#define SCK_PIN 2 // Clock pin connected to HX711 SCK

// Pin definitions for 4-digit display
#define CLK_PIN 4  // Clock pin for TM1637 display
#define DIO_PIN 5  // Data pin for TM1637 display

HX711 scale; // Create an HX711 object
TM1637Display display(CLK_PIN, DIO_PIN); // Create a TM1637 display object

void setup() {
  Serial.begin(9600); // Initialize serial communication for debugging
  scale.begin(DT_PIN, SCK_PIN); // Initialize HX711 with DT and SCK pins
  display.setBrightness(0x0F); // Set display brightness to maximum

  // Perform load cell calibration (adjust these values as needed)
  scale.set_scale(2280.f); // Set scale factor (calibration value)
  scale.tare(); // Reset the scale to zero
}

void loop() {
  // Read weight from HX711
  float weight = scale.get_units(10); // Average 10 readings for stability

  // Display weight on the 4-digit display
  display.showNumberDec(weight, false, 4, 0);

  // Print weight to the serial monitor for debugging
  Serial.print("Weight: ");
  Serial.print(weight);
  Serial.println(" kg");

  delay(500); // Wait for 500ms before the next reading
}

1. No Display Output:

   • Ensure the VCC and GND pins are properly connected to a 5V power source.
   • Verify the connections to the DIO and CLK pins of the display.

2. Inaccurate Weight Readings:

   • Perform proper load cell calibration using known weights.
   • Check for loose or incorrect connections to the load cell.

3. Fluctuating Readings:

   • Use a stable power supply and avoid electrical noise sources.
   • Ensure the load cell is securely mounted and not subject to vibrations.

4. No Communication with HX711:

   • Verify the connections to the DT and SCK pins.
   • Ensure the HX711 library is correctly installed in your Arduino IDE.

Q: Can I use this module with a 3.3V microcontroller?
A: The HX711 operates at 5V, but its data pins are 3.3V logic compatible. However, the 4-digit display requires 5V logic, so a level shifter may be needed for 3.3V microcontrollers.

Q: How do I calibrate the load cell?
A: Use a known weight to determine the scale factor. Adjust the set_scale() value in the code until the readings match the known weight.

Q: Can I connect multiple load cells to this module?
A: Yes, you can connect up to 4 load cells in a Wheatstone bridge configuration, provided their combined resistance is within the module's specifications.

Q: What is the maximum weight this module can measure?
A: The maximum weight depends on the load cell's capacity. Ensure the load cell's rating matches your application requirements.