BLE Gateway <-> MQTT

About

The scope of this project is to build a stable Bluetooth Low Energy Gateway which exchange messages with a MQTT Broker. The advantage of exchanging messages with a MQTT Broker is that a bi-directional connection can be enabled between the Bluetooth sensors and the Network Server.

This BLE Gateway implements a nice looking and easily operated Web Application which allows the user to easily manage the Bluetooth sensors inside the network.

The current version of the BLE Gateway accepts only two characteristics per device: notify characteristic and write characteristic.

The notify characteristic is used by the BLE Gateway to read the data sent by the Bluetooth sensors and publish them on MQTT Broker.

The write characteristic is used to send the data received from MQTT Broker to the Bluetooth sensors.

Example of a Bluetooth sensor implementation: BLE_write_read.ino

Web Application

Devices (/devices)

Features offered by /devices:

• Scan devices - discover bluetooth devices.
• Connect/Disconnect - connect or disconnect discovered bluetooth devices.
• Auto Discover - enable auto discover mode.
• Auto Connect - enable auto connect mode.

Configs (/configs)

Features offered by /configs:

• Gateway ID - unique identifier of the gateway (EUI64).
• MQTT Broker - set the MQTT Broker address on which the gateway is connecting.
• MQTT Subscribe/Publish Topics - define the MQTT Topics on which the gateway is listening and publish data.

API

GET /api/discover - start discover Bluetooth devices

GET /api/devices - get the list of devices discovered

POST /api/connect - connect a discovered device based on its uuid

• params: uuid

POST /api/disconnect - disconnect a device based on its uuid

• params: uuid

POST /api/auto - set auto_discover/auto_connect mode

• params:
  • auto_discover (true/false)
  • auto_connect (true/false)

Methods

readData() - Read messages received from devices and publish them to MQTT Broker

function readData(data) {
  console.log(this._peripheralId, data.readIntLE());

  // message example
  var message = {
    "uuid": this._peripheralId,
    "payload": data.readIntLE()
  }

  // Publish to MQTT Broker
  mqtt_client.publish(topic_rx, Buffer.from(JSON.stringify(message)));
}

sendData() - MQTT on message listener which sends the payload received from MQTT Broker to devices

function sendData() {
  mqtt_client.on('message', function(topic, message) {
    /*
    message = {
      uuid: "ble_device_uuid",
      payload: "payload_from_server"
    }
    */

    /* Send to a specific target */
    let msg = JSON.parse(message.toString('utf-8'));
    var uuid = msg['uuid'];
    var payload = msg['payload'];

    sendMessage(uuid, payload);
  });
}

sendMessage(uuid, payload) - Sends the payload to the specified device (uuid)

sendBroadcast(payload) - Broadcasts the payload to all connected devices

send message from MQTT Broker to Gateway

mosquitto_pub -h localhost -t "gateway/<gateway_id>/tx" -m '{
    "uuid": "<uuid>",
    "payload": "<payload>"
}'

Development

Install environment

macOS

brew install nodejs nginx
git clone https://github.com/bogdanoniga/ble_gateway.git
cd ./ble_gateway
npm install
mv ./nginx.conf /usr/local/etc/nginx/nginx.conf

Raspbian Stretch Lite (Raspberry Pi)

• Setting up your Raspberry Pi: RPi setup

• Setting up BLE Gateway: ./setup.sh

• Start/Stop ble_gateway.service

sudo systemctl start ble_gateway.service
sudo systemctl stop ble_gateway.service

• Read ble_gateway.service logs

journalctl -u ble_gateway.service -f

• Set ble_gateway.service to run at startup

sudo systemctl enable ble_gateway.service

Start dev environment

# macOS
# restart Bluetooth service
DEBUG=express-locallibrary-tutorial:* npm run devstart

# Raspbian
sudo service bluetooth restart
DEBUG=express-locallibrary-tutorial:* sudo npm run devstart

Technical Stack

• Noble BLE library (nodejs) - https://github.com/noble/noble
• Express (nodejs) - https://github.com/expressjs/express
• Nginx - https://github.com/nginx/nginx
• Dashgum Bootstrap template - https://github.com/esironal/dashgum-template

Todo

• Display the device services & characteristics
• Check if devices have disconnected
• Add passkey device authentication
• MQTT connection over TLS
• Web Authentication Method (Login User/Pass, Identity Plus)
• Settings page (change user, pass, authentication method)

MIT License

Copyright (c) 2018 Bogdan Oniga

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.