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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Node-Red – Storing IOT Data in a SQL Database
IOT data from sensors and other devices usually comes as either a text string usually with key value pairs or more commonly as JSON encoded data. Databases accept a variety of data formats the most common are INT and TEXT.
Continue readingHTTP Headers: Understanding HTTP Part 2
In the second part of our short http course we will look at http headers. If you’ve missed part 1 then here it is- Part 1- http basics
Continue readingUsing 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.
Continue readingNode-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.
Continue readingUsing The Node-Red Library
If you want to save a flow or function and reuse it later in another flow on the same computer then you can save it to the local library. To save a flow to the library highlight all nodes in the flow by using CTRL+A then use the main menu (top right) and select Export>Library.
Continue readingUnderstanding And Using MQTT v5 Request Response
Web Applications have a direct connection between the sender and receiver. The sender is the client (web browser) and the receiver is the server. They implement a command response message flow were the client(browser) makes a request and the server responds and there is a direct connection between client and server.
Continue readingMQTT v 5.0 New Features Overview
MQTT v5 introduced many new features and changed how some existing features work. In this tutorial I will be covering all of these features with brief examples, and also in many case, links to detailed examples and videos.
Continue readingDeploying Node-Red Flows
When you come to deploying a flow you have four (node-red v0.2)options as shown below: Although the choices appear obvious the effect of the options isn’t and can cause some confusion.
Continue readingHandling Multiple Client Connections-Python MQTT
It is common to require several connections either to a single broker or to several brokers. There a several ways of achieving this and we will examine two ways. First let us recap on what we require with a single connection.
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