Industrial Internet Application Development

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Preparing an SD card

To prepare an SD card, follow the sequence of actions as described:

Download the latest Raspbian LITE image (available at https://www.raspberrypi.org/downloads/raspbian/).
Connect your SD card to a computer and use Etcher (https://etcher.io/) to flash the Raspbian .img file to the SD card.
Enable SSH:

cd /Volumes/boot
touch ssh

To enable Wi-Fi, create wpa_supplicant.conf with the following content:

network={
 ssid="YOUR_SSID"
 psk="YOUR_WIFI_PASSWORD"
}

To create a file in a Linux console, you can use the GNU nano editor. It is pre-installed in most Linux distributives. All you need is to run the nano FILE_NAME command and follow the displayed instructions.

Create the /home/pi/hub folder.
Create the /home/pi/hub/package.json file with the following content:

{
 "name": "hub",
 "version": "1.0.0",
 "description": "",
 "main": "index.js",
 "scripts": {
   "start": "node index.js",
   "test": "echo \"Error: no test specified\" && exit 1"
 },
 "author": "",
 "license": "ISC",
 "dependencies": {
   "modbus": "0.0.16",
   "request": "^2.81.0"
 }
}

Create the /home/pi/hub/index.js file with the following content, replacing REMOTE-SERVER-ADDRESS.com and REMOTE-SENSOR-ADDRESS with real values:

var request = require('request');

var log = console.log;
//var mb = require('modbus').create(true); // enable debug output
var mb = require('modbus').create();

var sensor = 'REMOTE-SENSOR-ADDRESS';
var receiver = 'http://REMOTE-SERVER-ADDRESS.com:8080';

mb.onError(function (msg) {
  log('ERROR', msg);
});

// create master device
var ctx = mb.createMaster({

  // connection type and params
  con: mb.createConTcp(sensor, 1502),
  //con: mb.createConRtu(1, '/dev/ttyS1', 9600),

  // callback functions
  onConnect: function () {
    log('onConnect');
    log(ctx.getReg(2));
    ctx.setBit(1, false);

    //send to receiver
    var data = {
      device: 'sensor1',
      timestamp: Date.now(),
      reg2: ctx.getReg(2)
    };
    request.post({url: receiver, form: data}, function (err) {
      if (err) console.log('Failed to send to ' + receiver);
    });

    ctx.destroy();
  },
  onDestroy: function () {
    log('onDestroy');
  }
});

Create a /home/pi/hub/Dockerfile file with the following content:

FROM hypriot/rpi-node:boron-onbuild
RUN apt-get update && apt-get install -y libmodbus5

Create the /home/pi/sensor folder.

Create the /home/pi/sensor/package.json file with the following content:

{
"name": "sensor",
"version": "1.0.0",
"description": "",
"main": "index.js",
"scripts": {
  "start": "node index.js",
  "test": "echo \"Error: no test specified\" && exit 1"
},
"author": "",
"license": "ISC",
"dependencies": {
  "modbus": "0.0.16"
}
}

Create the /home/pi/sensor/index.js file with the following content, replacing REMOTE-HUB-ADDRESS.com with a real value:

var log = console.log;
var mb = require('modbus').create();

mb.onError(function (msg) {
 log('ERROR', msg);
});

// create device memory map
var data = mb.createData({ countReg: 5, countBit: 2 });
data.setReg(2, 321);
data.setBit(1, true);
data.dumpData(); // show memory map

// create slave device
var ctx = mb.createSlave({

 // connection type and params
 con: mb.createConTcp('REMOTE-HUB-ADDRESS.com', 1502),
 //con: mb.createConRtu(1, '/dev/ttyS0', 9600),

 // data map
 data: data,

 // callback functions
 onQuery: function () {
   log('onQuery');
   //ctx.dumpData();
   log(ctx.getBits(0, 2));
 },
 onDestroy: function () {
   log('onDestroy');
 }
});

// destroy device
//setTimeout(function () {
//
ctx.destroy();
//}, 5000);

Create the /home/pi/sensor/Dockerfile file with the following content:

FROM hypriot/rpi-node:boron-onbuild
RUN apt-get update && apt-get install -y libmodbus5