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EspruinoHub

A BLE -> MQTT bridge for Raspberry Pi and other Embedded devices

Setting up

Assuming a blank Raspberry Pi:

# Install a modern version of nodejs and nodered
sudo apt-get install build-essential python-rpi.gpio
bash <(curl -sL https://raw.githubusercontent.com/node-red/raspbian-deb-package/master/resources/update-nodejs-and-nodered)
# Get dependencies
sudo apt-get install mosquitto mosquitto-clients bluetooth bluez libbluetooth-dev libudev-dev
# Auto start Node-RED
sudo systemctl enable nodered.service
# Start nodered manually this one time (this creates ~/.node-red)
sudo systemctl start nodered.service
# Install the Node-RED UI
cd ~/.node-red && npm install node-red-contrib-ui
# Now get this repository
cd ~/
git clone https://github.com/espruino/EspruinoHub
# Install its' requirements
cd EspruinoHub
npm install
# Optional: Install espruino-web-ide to allow the IDE to be used from the server
git clone https://github.com/espruino/EspruinoWebIDE
# Give Node.js access to Bluetooth
sudo setcap cap_net_raw+eip $(eval readlink -f `which node`)

Note: On non-Raspberry Pi devices, Mosquitto (the MQTT server) may default to not allowing anonymous (un-authenticated) connections to MQTT. To fix this edit /etc/mosquitto/conf.d/local.conf and set allow_anonymous to true.

Note: The instructions above assume you want to use Node-RED. If you don't then you can skip the Node-RED related parts.

Usage

Run with start.sh (ideally you'd set this to auto-start - see below)

You then have a few options...

Status / Websocket MQTT / Espruino Web IDE

By default EspruinoHub starts a web server at http://localhost:1888 that serves the contents of the www folder. You can disable this by setting http_port to 0 in config.json.

With that server, you can:

  • See the Intro page
  • See the status and log messages at http://localhost:1888/status
  • Access the Espruino Web IDE at http://localhost:1888/ide if you install the espruino-web-ide NPM package (see the 'Setting up' instructions above). You can then connect to any Bluetooth LE device within range of EspruinoHub.
  • View real-time MQTT data via WebSockets at http://localhost:1888/mqtt.html
  • View any of your own pages that are written into the www folder. For instance you could use TinyDash with the code from www/mqtt.html to display the latest BLE data that you have received.

Node-RED / MQTT

You can access Node-RED using http://localhost:1880

Once you add UI elements and click Deploy they'll be visible at http://localhost:1880/ui

The easiest way to get data is to add an MQTT listener node that requests /ble/advertise/# (# is a wildcard). This will output all information received via advertising.

Useful MQTT advertising parts are:

  • /ble/presence/DEVICE - 1 or 0 depending on whether device has been seen or not
  • /ble/advertise/DEVICE - JSON for device's broadcast name, rssi and manufacturer-specific data
  • /ble/advertise/DEVICE/manufacturer/COMPANY - Manufacturer-specific data (without leading company code)
  • /ble/advertise/DEVICE/rssi - Device signal strength
  • /ble/advertise/DEVICE/SERVICE - Raw service data (as JSON)
  • /ble/advertise/DEVICE/PRETTY or /ble/PRETTY/DEVICE - Decoded service data. temp is the obvious one

To decode the hex-encoded manufacturer-specific data, try:

var data = Buffer.from(msg.payload.manufacturerData, 'hex');

You can also connect to a device:

  • /ble/write/DEVICE/SERVICE/CHARACTERISTIC connects and writes to the charactertistic
  • /ble/read/DEVICE/SERVICE/CHARACTERISTIC connects and reads from the charactertistic
  • /ble/notify/DEVICE/SERVICE/CHARACTERISTIC connects and starts notifications on the characteristic
  • /ble/ping/DEVICE connects, or maintains a connection to the device, and sends /ble/pong/DEVICE on success

After connecting, EspruinoHub will stay connected for a few seconds unless there is any activity (eg a write or ping). So you can for instance evaluate something on a Puck.js BLE UART connection with:

=> /ble/notify/c7:f9:36:dd:b0:ca/nus/nus_rx
"\x10E.getTemperature()\n" => /ble/write/c7:f9:36:dd:b0:ca/nus/nus_tx

Auto Start

There are a few ways to get services running all the time on a Raspberry Pi, but as it's got a video output it's nice to be able to use that as a status display.

To do this:

  • Edit .bashrc and add the following right at the bottom:
if [ $(tty) == /dev/tty1 ]; then
  while true; do
    EspruinoHub/start.sh
    sleep 1s
  done
fi

  • Now run sudo raspi-config, choose Boot Options, Desktop / CLI, and Console Autologin

  • Next time you reboot, the console will automatically run EspruinoHub

Alternatively, you can configure it as a system start-up job using systemd:

    sudo cp systemd-EspruinoHub.service /etc/systemd/system/EspruinoHub.service

and edit it as necessary to match your installation directory and user configuration. Then, to start it for testing:

    sudo systemctl start EspruinoHub.service && sudo journalctl -f -u EspruinoHub

If it works, enable it to start on login:

    sudo systemctl enable EspruinoHub.service

Testing MQTT

# listen to all, verbose
mosquitto_sub -h localhost -t /# -v

# Test publish
mosquitto_pub -h localhost -t test/topic -m "Hello world"

Note

To allow Bluetooth to advertise services (for the HTTP proxy) you need:

# Stop the bluetooth service
sudo service bluetooth stop
# Start Bluetooth but without bluetoothd
sudo hciconfig hci0 up

See https://github.com/sandeepmistry/bleno

Troubleshooting

When using the HTTP Proxy I get BLOCKED returned in the HTTP body

Your BLE device isn't in the whitelist in config.json - because the HTTP Proxy exposes your internet connection to the world, only BLE devices with the addresses you have specified beforehand are allowed to connect.

TODO

  • Keep connection open in connect.js for 30 secs after first write
  • Re-use the connection for queued requests
  • Handle over-size writes