BLEacon

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James Cranley, July 2025

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A lightweight ESP32-based RSSI logger and display for BLE beacons.

This project uses the Waveshare ESP32-S3-LCD-1.47 microcontroller with integrated LCD to monitor signal strength (RSSI) from a specific BLE beacon—typically a Shelly BLU Button1.
It displays live signal strength as text and signal bars, syncs its clock over NTP, and logs data to SD card.

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Hardware

• 📟 Waveshare ESP32-S3-LCD-1.47
  (ESP32-S3 microcontroller, 1.47" ST7789 LCD, HSPI interface)

• 🔘 Shelly BLU Button1
  (Bluetooth Low Energy beacon with long battery life)

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Preparing the Beacon

Ensure your Shelly BLU Button1 is in Beacon Mode:

1. Download the Shelly Smart Control app and pair your device.
2. In the app, tap on the Shelly Button1 and enable Beacon Mode under advanced settings.
3. Go to Device Info and note the MAC address—you'll need this for the sketch.

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Installation

1. Install Arduino IDE

• Install via Homebrew (for macOS):

  brew install --cask arduino-ide

• On Apple Silicon Macs, you may need Rosetta2:

  softwareupdate --install-rosetta

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2. Connect and Select the Board

• Plug the ESP32-S3-LCD-1.47 into USB.
• Open Arduino IDE.
• In the toolbar, select:
  • Board: “WAVESHARE ESP32-S3 LCD 1.47”
  • Port: Your device’s USB connection

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3. Install ESP32 Board Support

• Open the Boards Manager (left sidebar).
• Search for esp32 by Espressif Systems.
• Install the latest version.

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4. Install Required Libraries

• Open the Library Manager (left sidebar).
• Install the following:
  • Adafruit GFX Library
  • Adafruit ST7789 Library

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5. Load the Sketch

• Open the file: /src/multi_MAC_with_logging.ino
• Fill in:
  • The MAC addresses of your Shelly tags
  • Your Wi-Fi credentials for NTP time sync
• Upload to the device: Click the Upload button in the IDE.

If you get a Bad CPU Type error, then install rosetta2 (which is tiny), using softwareupdate --install-rosetta

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Output

The device will:

• Display current UTC time, MAC, SSID, and RSSI.
• It will log data to the on-baord micro SD card

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References

NHS Digital

Marini2020