BLE_SQLAcquisition

Proxy interface for transferring sensor data to a PostgreSQL database via Bluetooth Low Energy (BLE).

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Overview

BLE_SQLAcquisition is an asynchronous Rust application that bridges a Bluetooth Low Energy (BLE) network device (e.g., ESP32) with a PostgreSQL database.

It continuously scans for a specified target device, connects to it, subscribes to its INDICATE characteristic, buffers incoming sensor data, and inserts full datasets into PostgreSQL.
The service is designed to run in Docker and automatically handles reconnections and buffering.

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Features

• Automatic scanning for BLE devices with a configurable name
• Automatic connection and reconnection if the device becomes unavailable
• Dynamic discovery of the BLE INDICATE characteristic
• Data buffering until a full dataset of configurable size is received
• Direct PostgreSQL integration for inserting sensor data
• Configurable via environment variables
• Designed to run as a container alongside a PostgreSQL service

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Requirements

• Docker and Docker Compose installed on the host system
• A BLE adapter accessible from the container
• An ESP32 (or compatible) broadcasting under the name specified in docker-compose.yaml

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Database Schema

The application expects the following table in PostgreSQL:

CREATE TABLE PG_TABLE (
    id SERIAL PRIMARY KEY,
    datapoints REAL[],
    timestamp TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
);

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Configuration

All parameters are set via environment variables. When running through Docker Compose, these are defined in docker-compose.yaml.

Variable	Description
PG_USER	PostgreSQL username
PG_PASSWORD	PostgreSQL password
PG_HOST	PostgreSQL host (container name in Compose)
PG_DBNAME	Database name
PG_PORT	PostgreSQL port
PG_TABLE	Table to insert data
BLE_DEVICE_NAME	Name of BLE device to connect
DATA_SIZE	Number of datapoints per dataset
VALUE_BYTE_SIZE	Number of bytes per value (1, 2, or 4)

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Running with Docker Compose

1. Build and start the services:

docker compose -f bleproxy-compose.yaml up --build

2. The container will start:

   • ble_proxy (Rust BLE acquisition service)

3. Ensure the ble_proxy container has access to your BLE adapter by updating the devices section in docker-compose.yaml. Example:

devices:
  - "/dev/bus/usb/001/005:/dev/bus/usb/001/005"

Use lsusb or dmesg on the host to find the correct device path.

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Usage Notes

• The service retries automatically if the ESP32 disconnects or is unavailable
• All collected datasets (e.g., 3648 datapoints) are inserted into the PG_TABLE
• Values are parsed according to VALUE_BYTE_SIZE (1, 2, or 4 bytes)

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Project Status

Early-stage implementation intended as a BLE-to-SQL proxy.
Planned improvements:

• Configurable characteristic types
• Better error handling with exponential backoff
• Support for multiple devices and concurrent acquisitions
• Support for different database systems

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Credits

This Project was entirely written by me. Because of defecites regarding documentation skills, this readme was written using AI