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JavaScript in IoT

Jakub Jóźwiak

Agenda:

  1. Raspberry Pi
  2. AWS IoT
  3. Homebridge

Raspberry Pi

Cheap micro computer that runs Linux, but it also provides a set of GPIO pins that allow you to control electronic components.

Most popular micro computers


Micro Computer Price (around)
Raspberry Pi 4 ~ 190zł
Raspberry Pi Zero ~ 80zł
Arduino ~ 90zł
ESP8266 ~ 20zł
Shhh, these are your private notes 📝

How it looks like


What with those GPIO?


Types of sensors/inputs

  • Accelerometers
  • Gesture sensors
  • Fingerprint readers
  • LCD/LED screens
  • Temperature/Humidity sensors
  • Muscle sensors
  • Cameras
  • Many many more...

So how to code it?

onoff library 
                
const { Gpio } = require('onoff');
 
const LIGHT_PIN = 21;
const light = new Gpio(LIGHT_PIN, 'out');
 
// Turn on light
light.writeSync(1);
 
// Turn off light
light.writeSync(0);
 
const BUTTON_PIN = 2;
const button = new Gpio(
    BUTTON_PIN,
    'in',
    'rising',
    {debounceTimeout: 10}
);
 
button.watch(async (err, value) => {
    if (err) {
        throw err;
    }
 
    console.log('Button pressed!');
});

            
const { Gpio } = require('onoff');
 
const LIGHT_PIN = 21;
const light = new Gpio(LIGHT_PIN, 'out');
 
// Turn on light
light.writeSync(1);
 
// Turn off light
light.writeSync(0);
 
const BUTTON_PIN = 2;
const button = new Gpio(
    BUTTON_PIN,
    'in',
    'rising',
    {debounceTimeout: 10}
);
 
button.watch(async (err, value) => {
    if (err) {
        throw err;
    }
 
    console.log('Button pressed!');
});
const { Gpio } = require('onoff');
 
const LIGHT_PIN = 21;
const light = new Gpio(LIGHT_PIN, 'out');
 
// Turn on light
light.writeSync(1);
 
// Turn off light
light.writeSync(0);
 
const BUTTON_PIN = 2;
const button = new Gpio(
    BUTTON_PIN,
    'in',
    'rising',
    {debounceTimeout: 10}
);
 
button.watch(async (err, value) => {
    if (err) {
        throw err;
    }
 
    console.log('Button pressed!');
});
const { Gpio } = require('onoff');
 
const LIGHT_PIN = 21;
const light = new Gpio(LIGHT_PIN, 'out');
 
// Turn on light
light.writeSync(1);
 
// Turn off light
light.writeSync(0);
 
const BUTTON_PIN = 2;
const button = new Gpio(
    BUTTON_PIN,
    'in',
    'rising',
    {debounceTimeout: 10}
);
 
button.watch(async (err, value) => {
    if (err) {
        throw err;
    }
 
    console.log('Button pressed!');
});

Scheduling tasks

So probably You would like to run your app automatically on system reboot or with specific time pattern.

Run in terminal: 
                    
crontab -e
And add script at the end of file: 
                    
@reboot node /home/pi/app.js &

And what can You really do with this micro-computer?

  • Use as Your Desktop PC
  • Security camera
  • NAS
  • WiFi extender
  • Smart mirror
  • Ambilight System for any screen
  • And again many many more...

"It works for me"

AWS IoT

You know how to code Your device but how to securely connect with Your app?
AWS IoT provides the cloud services that connect your IoT devices to other devices and AWS cloud services.
  • Managing devices
  • Security
  • Monitoring
  • Over-the-air-updates

Sounds good? Implementation is much better!

AWS IoT Device SDK JS 
                
const awsIot = require('aws-iot-device-sdk');
 
const device = awsIot.device({
    keyPath: 'PrivateKeyPath',
    certPath: 'CertificatePath',
    caPath: 'RootCACertificatePath',
    clientId: 'UniqueClientIdentifier',
    host: 'IoTCoreEndpoint'
});
 
device.on('connect', () => {
    console.log('connected');
    device.publish('connected', JSON.stringify({ message: 'connected' }));
    device.subscribe('turnOn');
});
 
device.on('message', (topic) => {
    if (topic === 'turnOn') {
        console.log('Turned on');
    }
});

            
const awsIot = require('aws-iot-device-sdk');
 
const device = awsIot.device({
    keyPath: 'PrivateKeyPath',
    certPath: 'CertificatePath',
    caPath: 'RootCACertificatePath',
    clientId: 'UniqueClientIdentifier',
    host: 'IoTCoreEndpoint'
});
 
device.on('connect', () => {
    console.log('connected');
    device.publish('connected', JSON.stringify({ message: 'connected' }));
    device.subscribe('turnOn');
});
 
device.on('message', (topic) => {
    if (topic === 'turnOn') {
        console.log('Turned on');
    }
});
const awsIot = require('aws-iot-device-sdk');
 
const device = awsIot.device({
    keyPath: 'PrivateKeyPath',
    certPath: 'CertificatePath',
    caPath: 'RootCACertificatePath',
    clientId: 'UniqueClientIdentifier',
    host: 'IoTCoreEndpoint'
});
 
device.on('connect', () => {
    console.log('connected');
    device.publish('connected', JSON.stringify({ message: 'connected' }));
    device.subscribe('turnOn');
});
 
device.on('message', (topic) => {
    if (topic === 'turnOn') {
        console.log('Turned on');
    }
});

Homebridge

So if it comes to IoT probably mostly there is Smart Home in the background.

Homebridge allows you to integrate with smart home devices that do not natively support HomeKit without any costs or effort.

How to install homebridge on RPI

Install homebridge globally 
                
sudo npm install -g --unsafe-perm homebridge homebridge-config-ui-x
Setup homebridge as a service that will start on boot 
                
sudo hb-service install --user homebridge
Login to the web interface by going to http://{ip address of your server}:8581.

Recommended plugins for presentation context

  • Homebridge MQTT-Thing
  • Homebridge RPi

There are over 2,000 Homebridge plugins supporting thousands of different smart accessories.
Also you can create your own plugin!

Additional helpful sites

  • Forbot blog
  • Botland shop
  • Nest.js MQTT microservice module
  • Node-RED - Online and drag&drop service for wiring together hardware devices

THE END