Working with Bluetooth using Node.js and node-red from Intel Edison

1. Background

If you are working with Intel Edison then you must have already discovered that getting bluetooth to work in any sensible way in Edison is just a dead end. More so, if you are looking for a workaround with Node.js or node-red.

After hours of trail and errors, I could get it to work. So I am crating this page. Hope it saves someone's precisous time!

I would tell you the logic first. Intel Edison Bluetooth does not have a Serial port service which is important for phone-Edison communication. Intel has a Python script that provides Serial port service. A mod of this python script was written to write the data to a named pipe which could then be read from programs like Arduino.

Bad news is that javascript does not and will probably never support named pipes. So we write a bash script to read data from named pipe. Now using a command line websocket we publish the data being received by this shell script.

Now we install websocket and ws ( a client) with npm to enable Node.js to work with websockets. Using websocket client we listen to our deamon server.

Android Mobile--> Serial Port--> Python Background Script--> Named Pipe---> Bash Script--> Websocket-->Javascript.

Don't get afraid. Steps aren't too complicated. It works like a charm.

1) Unblock Bluetooth:

rfkill unblock bluetooth

2) Login to Bluetooth Console

bluetoothctl

3) Make discoverable

discoverable on

4) scan for the bluetooth device:

scan on

once the device is seen in list, ctrl+c

6) Pair 

pair <DEv_ID>

7) Connect to Bluetooth Device

connect <DEv_ID>

8) Trust the Device 

trust <DEv_ID>

9) Download Android bluetooth SPP app

 Android Bluetooth SPP Pro ( Free)

10) Now we need to follow This Intel Tutorial Here

Quote:

a) download :https://software.intel.com/sites/default/files/managed/6c/16/bluetooth-service.tar.gz
b) using WinScp to upload the file to /home/root
c) untar the package

mkdir /home/root/bluetooth
cd /home/root/bluetooth
mv /home/root/bluetooth-service.tar.gz ./
tar -xvf bluetooth-service.tar.gz

 

d) Prepare for Bluetooth at startup

cp bluetooth-spp-pin.service /lib/systemd/system

 systemctl enable bluetooth-spp-pin

<span style="margin: 0px; padding: 0px; border: 0px; color: rgb(17, 17, 17); font-family: 'Segoe UI', Arial, sans-serif; font-size: 14px; background-color: rgb(238, 238, 238);">reboot</span>

e) after login back:

systemctl status bluetooth-spp-pin

11) This package has a file by name bluetooth-spp-service.py which runs serial port service and release them in a named pipe: /tmp/arduino_pipe_out
So now we need to write a bash script that can read from this named pipe

12) vi readPipe.sh

#!/bin/bash

pipe=/tmp/arduino_pipe_out

trap "rm -f $pipe" EXIT

if [[ ! -p $pipe ]]; then
    mkfifo $pipe
fi

while true
do
    if read line <$pipe; then
        if [[ "$line" == 'quit' ]]; then
            break
        fi
        echo $line
    fi
done

echo "Reader exiting"
​

esc :wq to come out from editor saving the file.

13) Make it Executable

chmod 755 readFile.sh

14) Execute it to test that you are able to fetch command being sent through bluetooth

./readFile.sh 

It will now wait for a bluetooth command. From your app, generate bluetooth command

You will see that is appearing in the command prompt

15) Websocket

javascript does not support pipes. So we need to release it using websocket.  Download websocketd  a command based websocket deamon. Unzip. copy the file websocketd to /home/root
from /home/root

chmod 755 websocketd

16) run the deamon  server

./websocketd --port=8080 ./readPipe.sh

16)Test with node-red

Now go to your node red.from input palatte take Websocket

change:
Type: Listen On
Path: /ws://localhost:8080

Connect it to debugger. Deploy. Now generate command from your android app. You will be able see the result in node-red

17) Test With Node.js

Install websocket first.

npm install websocket

Install ws, a lightweight websocket client

npm install ws

Write Node.js simple client to test it. say myWsClient.js

var WebSocket = require('ws')
  , ws = new WebSocket('ws://localhost:8080');
ws.on('open', function() {
    ws.send('something');
});
ws.on('message', function(message) {
    console.log('received: %s', message);
});

Run it with 

node myWsClient

That's all. Now you can receive commands from your Bluetooth enabled Android mobile to Intel Edison.