The HX711 is a precision 24-bit analog-to-digital converter (ADC) designed for applications requiring high accuracy and stability, such as weigh scales and industrial control systems. It features an integrated low-noise programmable gain amplifier (PGA) that allows direct interfacing with load cells, making it an ideal choice for weight measurement systems. The HX711 simplifies the process of converting small analog signals from load cells into digital data that can be processed by microcontrollers.
This circuit is a weighing system that uses two load cells connected to HX711 modules for weight measurement, interfaced with an Arduino Mega 2560. The system includes an LCD for displaying weight, a Bluetooth module for wireless communication, and LEDs for status indication, with a micro servo for additional mechanical control.
Open Project in Cirkit Designer
This circuit integrates multiple HX711 weighing sensor modules connected to load cells for weight measurement, an OV7725 camera module interfaced with a Raspberry Pi 4B for image capture, and a WeMOS ESP8266 for wireless communication. Additionally, it includes an Adafruit 24-Channel PWM LED driver for controlling LEDs and a buzzer module for audio alerts.
Open Project in Cirkit Designer
This circuit uses an Arduino Mega ADK to interface with an HX711 weighing sensor module to measure weight. When the weight exceeds a predefined threshold, the Arduino lights up a red LED for 60 seconds. The system is designed to detect and indicate the presence of a raindrop or similar event.
Open Project in Cirkit Designer
This circuit is a multi-sensor data acquisition system powered by a 18650 battery and managed by an ESP8266 microcontroller. It includes a load sensor interfaced with an HX711 module for weight measurement, an IR sensor, an ADXL345 accelerometer, a VL53L0X distance sensor, and a Neo 6M GPS module for location tracking. The system is designed for wireless data transmission and is supported by a TP4056 module for battery charging.
Open Project in Cirkit DesignerThe HX711 is designed to provide high precision and ease of use. Below are its key technical details:
| Parameter | Value |
|---|---|
| Supply Voltage | 2.6V to 5.5V |
| Operating Current | ~1.5mA |
| Standby Current | <1µA |
| ADC Resolution | 24-bit |
| Input Channels | 2 (Channel A and Channel B) |
| PGA Gain | 128 (Channel A) / 64 (Channel B) |
| Data Rate | 10 Hz or 80 Hz |
| Input Voltage Range | ±40mV (with gain of 128) |
| Communication Interface | Serial (Clock and Data pins) |
| Operating Temperature Range | -40°C to +85°C |
The HX711 has 16 pins, but only a subset is typically used in most applications. Below is the pin configuration:
| Pin Name | Description |
|---|---|
| VCC | Power supply input (2.6V to 5.5V). |
| GND | Ground connection. |
| DT (DOUT) | Serial data output. Connects to the microcontroller for data communication. |
| SCK (CLK) | Serial clock input. Used to control data transmission and gain selection. |
| RATE | Data rate selection pin. Low = 10 Hz, High = 80 Hz. |
| AVDD | Analog power supply for the load cell. Typically connected to VCC. |
| A+ / A- | Differential input for Channel A (high-precision input with gain of 128). |
| B+ / B- | Differential input for Channel B (lower precision input with gain of 64). |
The HX711 is straightforward to use in a circuit, especially for weight measurement applications. Below are the steps and considerations for using the HX711:
Below is an example of how to interface the HX711 with an Arduino UNO to read weight data:
#include "HX711.h" // Include the HX711 library
// Define HX711 pins
#define DT_PIN 3 // Data pin connected to D3 on Arduino
#define SCK_PIN 2 // Clock pin connected to D2 on Arduino
HX711 scale; // Create an instance of the HX711 class
void setup() {
Serial.begin(9600); // Initialize serial communication
scale.begin(DT_PIN, SCK_PIN); // Initialize HX711 with defined pins
// Wait for the HX711 to stabilize
Serial.println("Initializing HX711...");
delay(1000);
// Set the scale to zero (tare)
Serial.println("Taring the scale...");
scale.set_scale(); // Set the scale factor (calibration required later)
scale.tare(); // Reset the scale to zero
Serial.println("Scale is ready.");
}
void loop() {
// Read weight data from the HX711
if (scale.is_ready()) {
float weight = scale.get_units(); // Get weight in units (calibration required)
Serial.print("Weight: ");
Serial.print(weight);
Serial.println(" units");
} else {
Serial.println("HX711 not ready. Check connections.");
}
delay(500); // Wait before the next reading
}
scale.set_scale() with a calibration factor specific to your load cell.No Data Output:
Unstable or Noisy Readings:
Incorrect Weight Measurements:
HX711 Not Ready:
scale.is_ready() function is used correctly.Q: Can the HX711 be used with a 3.3V microcontroller?
A: Yes, the HX711 operates with a supply voltage range of 2.6V to 5.5V, making it compatible with both 3.3V and 5V systems.
Q: How do I select between Channel A and Channel B?
A: The gain setting determines the active channel:
Q: What is the maximum weight the HX711 can measure?
A: The maximum weight depends on the load cell used. The HX711 itself does not impose a weight limit but converts the load cell's output signal.
Q: Can I use multiple HX711 modules in one system?
A: Yes, multiple HX711 modules can be used, but each module requires its own set of data (DT) and clock (SCK) pins on the microcontroller.
By following this documentation, you can effectively integrate the HX711 into your projects for precise weight measurement and control.