Using MQTT-Lens- Beginners Guide

MQTT Lens is an add-on for the chrome browser that lets you publish messages to an MQTT broker and subscribe to MQTT topics and receive messages using the chrome web browser. Once installed you access it via the url chrome://apps as shown below:

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MQTTv5 Connect and Connack Messages -Overview

The MQTT CONNECT and response messages (CONNACK) have been greatly enhanced in MQTTv5 with the addition of the properties field. This allows for a large increase in the information that can be exchanged on connection establishment compared to MQTT v3.11. The properties field can be found in both the CONNECT and CONNACK , DISCONNECT and other messages. The purpose of this tutorial is to provide an overview of the CONNECT message in MQTTv5 and a quick Comparison with MQTT v3.11.

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Using HTTP APIs For IOT -Beginners Guide

Many of the APIs today are Web API’s designed to access web services like Facebook ,Twitter etc. Because of their widespread use most IOT services (AZURE,AWS,Bluemix)  also support http based APIs. To understand and use an http API you will need a reasonable understanding of the following:

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JSON For Beginners

When sending and receiving data in IOT applications and APIs you will encounter JSON formatted data. Having a good working knowledge of JSON and how to create and use JSON data will be very important in developing IOT applications.

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Using cURL for Testing IOT Applications

The http protocol is the main protocol used on the web, and because of its widespread adoption it is also used in IOT applications. Many IOT applications like the Thingsboard Dashboard support both http and MQTT. In this tutorial we will start with a general introduction to cURL and show examples of using cURL to get and POST data.

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Node-Red Flows – Storage and Backup

Flows that you create are stored by default in a file in the .node-red directory of your home folder in a file called flows_servername.json. The file is created when you run node-red for the first time, and is loaded each time that you run node-red.

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Node-Red Settings.js File – Node-Red Admin

Node red uses a settings file called settings.js located in in the user .node-red (dot node-red) folder in their home directory. You can create your own settings file and customise it either by copying the existing file or using the file available from Github here. On Linux the settings.js file is copied from the /usr/lib/node-modules/node-red/ folder to your .node-red folder in your home directory when you start node-red, and there is no settings.js file present.

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