DEPRECATED

The Skygear IoT plugins only works with Skygear v0, but not in latest v1.

Create your first Skygear IoT application

In this tutorial, we will create a system with 3 parts:

• Devices will save a temperature reading to the Skygear Cloud Database on request
• Server will request a reading from devices every 5 minutes using a PubSub channel
• If the reported temperature is higher than 70C, the server will broadcast a warning.

Client-Side Code

First we will create a user application on the RespberryPi. In the /home/pi/skygear-iot directory create a folder named user-app and a file named package.json inside with the following contents:

{
  "name": "user-app",
  "version": "1.0.0",
  "main": "index.js",
  "dependencies": {
    "skygear": "^0.22.1"
  }
}

This file contains metadata about your user application which will be loaded by the Skygear IoT Client. Next, create a file named index.js inside user-app with the following contents:

const skygear = require('skygear');
const skygearIot = require('../skygear-iot.js');

const TemperatureRecord = skygear.Record.extend('temperature');

async function main() {
  console.log('Waiting for temperature requests...');
  while(true) {
    await skygearIot.pubsub.one('request-temperature');
    // randomly generate a temperature between 30-80
    // because we don't have a physical sensor connected
    const temperature = 30 + 50 * Math.random();
    await skygear.publicDB.save(
      new TemperatureRecord({temperature})
    );
    console.log(`Temperature Sent: ${temperature}C`);
  }
}

module.exports = main();

Your file structure should now look something like this:

/home/pi/skygear-iot
├── config.json
├── ...
└── user-app
    ├── index.js
    └── package.json

Now restart the Skygear IoT client using sudo systemctl restart skygear-iot and it should load your newly created application:

The device is now ready, we can set it aside and begin configuring the server.

Before proceeding any further, you should familiarize yourself with Skygear Cloud Code by following the Cloud Code Introduction Guide.

Scheduled Tasks using Cloud Code

In an empty folder on your computer, create a file named __init__.py with the following contents:

import skygear
from skygear.pubsub import publish

@skygear.every('@every 5m')
def request_temperature():
    publish('request-temperature', {})

The request_temperature function will be called every 5 minutes and publish a request event. Deploy this code to your skygear server to see it in action, you should be able to see temperature readings from your device in 5 minutes after the server has restarted successfully.

Database Event Hooks using Cloud Code

Now we will add one more function to __init__.py to check if the reported temperatures are higher than 70C:

import skygear
from skygear.pubsub import publish

@skygear.every('@every 5m')
def request_temperature():
  publish('request-temperature', {})

@skygear.after_save('temperature')
def check_temperature(record, *_):
  if record['temperature'] > 70:
    publish('high-temperature', {
      'device':       record['created_by'],
      'temperature':  record['temperature']})