This project uses a Dasduino CONNECTPLUS (ESP32), an Ultrasonic Distance Sensor, and a MAX98357A I²S Audio Amplifier to create an intelligent sound warning system.
When the ultrasonic sensor detects an object at approximately 40 cm (±3 cm) for more than 5 seconds, it plays a custom audio file (done.wav) from a microSD card through two connected speakers.
The project can also be manually controlled over the Serial Monitor, allowing you to:
- Play the sound once
- Enable/disable looping playback
- Enable/disable ultrasonic detection
- Adjust audio volume in real time
It’s ideal for industrial automation, machine status indication, or any system where a clear, audible feedback signal is required.
- Dasduino CONNECTPLUS
- Ultrasonic Distance Sensor (easyC)
- MAX98357A I²S Audio Amplifier
- Speaker 0.5 W / 8 Ω
- microSD Card Module
- microSD card (formatted FAT32) with a file named
/done.wav
- Arduino IDE
- ESP32-audioI2S Library
- Ultrasonic Distance Sensor easyC Library
- Built-in:
SD.h,FS.h
- If you haven’t already, install Arduino IDE
- Download this repository and extract it
- Open the Arduino sketch:
audio-amplifier-warning-sensor-project/audio-amplifier-warning-sensor-project.ino - Open the Boards Manager and search for ESP32 by Espressif Systems, then install it
- Under Tools → Board, select ESP32 Dev Module and the correct serial port
- Set:
- PSRAM: Enabled
- Partition Scheme: No OTA (Large APP)
- Install all of the libraries listed under Software Requirements
- Place your audio file on a FAT32-formatted SD card and rename it to
done.wav
(You can use any.wavfile you like — a beep, tone, alert, or even a short melody. Just make sure it’s 16-bit PCM, 44.1 kHz.) - Wire the components as described below and upload the sketch
No credentials or additional configuration are needed for this project.
- Upon startup, the serial monitor (115200 baud, No line ending) displays available commands.
- You can control the system using the following single-character commands:
Command Action pPlay the sound once lStart loop playback (every 5 seconds) sStop loop playback uEnable ultrasonic detection zDisable ultrasonic detection 0–21Set volume (0 = mute, 21 = max) - When ultrasonic detection is active and an object stays at ~40 cm ±3 cm for 5 seconds, the system plays
/done.wav. - You can monitor the measured distance in real time through the serial output.
- Adjust volume or stop/start detection at any time.
- Replace
done.wavanytime to change the sound the device plays.
| Component | Pin on Dasduino | Notes |
|---|---|---|
| MAX98357A VCC | 5V | Power |
| MAX98357A GND | GND | Common ground |
| MAX98357A BCLK | GPIO26 | I²S bit clock |
| MAX98357A LRCLK | GPIO25 | I²S left/right clock |
| MAX98357A DIN | GPIO27 | I²S audio data |
| microSD VCC | 3.3V (or 5V if supported) | Power |
| microSD GND | GND | Common ground |
| microSD MOSI | GPIO23 | SPI data output |
| microSD MISO | GPIO19 | SPI data input |
| microSD SCK | GPIO18 | SPI clock |
| microSD CS | GPIO33 | Chip select |
| Ultrasonic (easyC) | Qwiic/easyC port | Uses I²C (GPIO21/22) |
| Speakers | L+, L– / R+, R– | Connect to amplifier outputs |
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