Project by Pinout Crew for Ala Praxis

Sand-of-time

Weight-Based Audio Player

This project uses a load cell with HX711 amplifier and a DFPlayer Mini MP3 module to create an audio system where the playback volume is controlled by the weight measured on the load cell. The audio loops continuously while the weight is applied.

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Components & Connections

1. Arduino Nano

• Main microcontroller.

2. HX711 (Load Cell Amplifier)

• VCC → 5V (Arduino)
• GND → GND (Arduino)
• DT → A1 (Arduino analog pin)
• SCK → A0 (Arduino analog pin)
• Load Cell → HX711 E+ / E- / A+ / A- (follow module pinout)

3. DFPlayer Mini

• VCC → 5V (Arduino)
• GND → GND (Arduino)
• RX → D10 (Arduino)
• TX → D11 (Arduino)
• SPK_1 / SPK_2 → Speaker (8Ω recommended)

4. Power

• A stable 5V source (USB or regulated supply).
• If using an external supply, make sure Arduino and modules share the same ground.

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Libraries Used

1. HX711 Arduino Library
   HX711 by Bogde
   For reading weight from the load cell via HX711.

2. DFRobotDFPlayerMini
   DFRobotDFPlayerMini Library
   For controlling the DFPlayer Mini (play, loop, volume, etc.).

3. Software Serial Library [https://github.com/PaulStoffregen/SoftwareSerial]

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How It Works

1. The load cell measures weight through the HX711.
2. Arduino reads the weight value.
3. DFPlayer Mini plays an audio file in a loop.
4. The playback volume is adjusted dynamically based on the weight detected.

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Troubleshooting

• No sound?

  • Check speaker connection (SPK1 & SPK2).
  • Make sure your audio file is in the mp3 or 01 folder on the SD card.
  • File should be named like 0001.mp3, 0002.mp3, etc.

• Wrong weight reading?

  • Verify wiring between load cell and HX711.
  • Use correct HX711 pins (DT → A1, SCK → A0).
  • Try calibrating by placing a known weight.

• Distorted sound?

  • Use an 8Ω speaker, not a buzzer.
  • Ensure stable 5V power supply.

• DFPlayer not detected?

  • Check if the SD card is FAT32 formatted.
  • Ensure RX/TX pins are correctly wired (crossed: Arduino D10 → DFPlayer TX, Arduino D11 → DFPlayer RX).
  • Add a 1K resistor in series with the DFPlayer RX pin if it’s unstable.

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Future Improvements

• Add an LCD display to show weight.
• Allow multiple audio tracks depending on weight ranges.
• Implement calibration mode for more accurate measurements.