Can't open websocket on mobile devices

Question

I am attempting to set up a websocket with server running on my raspberry pi. The following code is slightly modified from an example I found here.

I have built a wh

Answer 1

For the hostnames of the devices to work across network, a device has to advertise its own hostname or just responding to DNS queries for its own hostname.

Whatever implementation the Raspberry Pi is using, your laptop is supporting it, but your phone isn't.

So, to be able to connect, you need to change your hostname raspberrypi-mike to your Raspberry Pi's IP address, inside your JavaScript code.

Answer 2

ADDED SOME EXTRA CODE

I would recommend using node.js for that:

var express = require("express");
var app = express();
var http = require("http").Server(app);
var path = require("path");
var io = require('socket.io')(http);
var SerialPort = require('serialport');
var gpio = require('rpio');

http.listen(3000);

var serialPort = new SerialPort.SerialPort("/dev/ttyAMA0", {
    baudrate: 115200,
    dataBits: 8,
    parity: "none",
    stopBits: 1,
    flowControl: false
});

io.on('connection', function(socket){
    console.log('Connected');
    socket.on("WriteSerial:get",function(data){
            var hex = new Buffer (data, "hex"); //be careful passing data
            writeSerial(serialPort, hex);
            io.emit("WriteSerial:response", "Data writen!");
    });
    socket.on("ReadGPIO:get",function(data){
            var input = readPin(data.pin); 
            io.emit("ReadGPIO:response", input); 
    }); 
    socket.on("WriteGPIO:get",function(data){
            writePin(data.pin, data.time); 
            io.emit("WriteGPIO:response", "Set!"); 
    }); 
    socket.on("unWriteGPIO:get",function(data){
            unwritePin(data); 
            io.emit("unWriteGPIO:response", "Set!"); 
    });        
}
app.use(express.static(path.join(__dirname, '/')));
app.get("/home",function(req,res,next){
    res.sendFile(path.join(__dirname + "/index.html"));
});

function writeSerial (port, data)   {
    port.write(data, function(err) {
        if (err) {
            return console.log('Error on write: ', err.message);
        } else {
            console.log('Data written: ' + data);
        }
    });
}

function readPin(pin){
    rpio.open(pin, rpio.INPUT);
    var read = rpio.read(pin) ? 'high' : 'low';
    return read;
}

function writePin(pin, timeInMs){
    rpio.open(pin, rpio.OUTPUT, rpio.LOW);
    rpio.write(pin, rpio.HIGH);
    if (timeInMs > 0) {
        setTimeout(function(){
            rpio.write(pin, rpio.LOW); 
        }, timeInMs);
    } //You can put 0 if You want it to be high until You shut it down 
}

function unWritePin(pin){
    if(readPin(pin) === 'high') {
        rpio.write(pin, rpio.LOW);
    } else {
        console.log("Pin already low!");
    }
}

Be sure You have instaled the node.js with right version. If not do this in terminal:

sudo apt-get remove nodered && sudo apt-get remove nodejs nodejs-legacy && curl -sL https://deb.nodesource.com/setup_4.x | sudo bash - && sudo apt-get install -y nodejs

Make a folder 'server' in '/home/pi/', add server.js to it. Add code I provided to server.js. Open that folder with terminal:

cd /home/pi/server/

Afther that install all modules used on server:

sudo npm install express && sudo npm install http && sudo npm install path && sudo npm install socket.io && sudo npm install serialport --unsafe-perm && sudo npm install rpio --unsafe-perm

Now all we have to do is create client side part. In folder '/home/pi/server' create index.html file and add folder called 'js'. In folder 'js' add socket.io.js for client side which You can find in folder '/home/pi/server/node_modules/socket.io/node_modules/socket.io-client/'.

Include socket.io.js for client side into Your index.html like this:

<script type="text/javascript" src="js/socket.io.js" /></script>

Also add main.js file to 'js' folder where You will put Your javascript code in and include it to index.html:

<script type="text/javascript" src="js/main.js" /></script>
<script type="text/javascript" src="js/jquery.js" /></script>

I will not make any graphics for but some main.js code is here:

$(document).ready(function() {
    var socket = io.connect('http://your_ip_address_rpi:3000');

    $( "#myButton" ).click(function(){
        io.emit("WriteSerial:get", $("#myTextHolder").val()); //"FAAF531C" this is string of hex, should be added some filter to pass error when char is not part of HEX!
    });
    $( "#myButton2" ).click(function(){
        io.emit("WriteGPIO:get", {"pin" : $("#myPinHolder").val(), "time" : $("#myTimeHolder").val()})

}

To run server on RPI startup add 'sudo node /home/pi/server/server.js &' to '/etc/rc.local' before 'exit 0' with 'sudo nano' editor.

It will work really good on any device.