EspruinoHub

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

Setting up

Assuming a blank 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

# 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.

Usage

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

You can then 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 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 and rssi
• /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

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

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