Example Code to Send HX711 Weight Data from ESP32 to Smartphone via Bluetooth

p.kaczmarek2 wrote:

Show example code to load into ESP32 controller that allows to send the weigh data from a HX711 to Bluetooth in my smartphone

To send weight data from an HX711 load cell amplifier to a smartphone via Bluetooth using an ESP32, you can follow the example code provided below. This code will guide you through setting up the necessary libraries, initializing the HX711 and Bluetooth, and sending the weight data to your smartphone.

Step 1: Hardware Connections
1. HX711 to ESP32:
- VCC to 3.3V
- GND to GND
- SCK to GPIO18
- DT to GPIO19

Step 2: Software/Library Installation
1. Ensure you have the latest Arduino IDE installed.
2. Install the HX711 library for Arduino.
3. Install the ESP32 board package in Arduino IDE.
4. Include the BluetoothSerial library which is inbuilt with the ESP32 core.

Step 3: Example Code

Here’s a simple example code to read data from the HX711, process it, and send it via Bluetooth to your smartphone.



Step 4: Explanation and Alternatives

1. Initialization:
- The `HX711` library is used to interface with the load cell amplifier.


- Calibration and taring of the scale should be customized per your exact hardware setup.

Replace `-2280.f` with your specific calibration factor which you can find using a known weight.

2. Bluetooth Data Transmission:
- Initializing Bluetooth serial communication with:


- You can alter `"ESP32_Scale"` to any desired Bluetooth device name.

3. Code Loop:
- The `loop()` function repeatedly reads the weight and sends it via Bluetooth typically every half second (`delay(500)`).

4. Error Handling:
- Checking if the `HX711` is ready:

This handles the case if there is a loose connection or the sensor is malfunctioning.

Additional Tips:

- Calibration:
Test and calibrate your scale setup with known weights. Adjust the value passed in `set_scale()` for accurate measurements.

- Bluetooth Integration:
Use any generic Bluetooth terminal app on your smartphone to receive and monitor the weight data sent by the ESP32.

- Power Supply:
Ensure your power supply is stable, particularly when using the HX711, which can be sensitive to power fluctuations.

- Debugging:
Use Serial Monitor extensively during development to verify the values read and troubleshoot issues.

Conclusion

This setup offers a basic but comprehensive approach to interfacing an `HX711` with an `ESP32` and sending data over Bluetooth. Modify the example code based on your specific needs, particularly concerning calibration and sensor read delay. Feel free to ask more questions if you encounter any issues or need additional features!

Would you like further assistance with calibration, power considerations, or a more advanced Bluetooth implementation?