Most MQTT implementations use SSL by default for data security. However SSL is a link encryption method and doesn’t secure the payload end to end unless SSL is applied to all links. In addition if the data is stored at the destination it will be unencrypted unless it is encrypted before storage. Click to rate this post! [Total: 0 Average: 0]Continue reading
It has always been possible to store JSON Data in an SQLite database as JSON data is simply text data. However what was not previously possible was how to query this JSON data using a key. This changed in version 3.9 in 2015 (SQLite history) and so there is now no need to separate out the JSON data so that you can query using a key. . Click to rate this post! [Total: 5 Average: 4.2]Continue reading
Today most of the data we receive across the Internet is received using the HTTP protocol. HTTP is the protocol that powers the Web,and is the most common protocol on the Internet. HTTP was designed for viewing static web pages and uses a request/response technique for viewing a web page. Click to rate this post! [Total: 1 Average: 5]Continue reading
Prior to node-red version 2.1 an MQTT node would auto connect when the flow was started and it was not possible to disconnect from a broker. In addition the subscribe node was configured with a topic, and it wasn’t possible to subscribe to additional topics or unsubscribe from topics once the flow had started. Click to rate this post! [Total: 5 Average: 5]Continue reading
Some nodes like the MQTT-in and MQTT-out nodes share configuration data. The MQTT-in and MQTT-out nodes share the broker configuration. Settings like broker address, port, clean sessions,authentication are part of the configuration node. Click to rate this post! [Total: 0 Average: 0]Continue reading
This tutorial is part of a series of project tutorials I will be creating for beginners looking to get familiar with node-red by creating actual flows. In this simple project we will look at splitting a simple message payload, and then display the data in a text box and on gauges on a dashboard. The payload consists of a simple string containing temperature and humidity readings separated by a ampersand (&). Click to rate this post! [Total: 1 Average: 4]Continue reading
A flow is a collection of nodes wired together and appears as a tab in the workspace. Flows are the main way of organising nodes. A flow has a context variable associated with it which is available to all nodes in the flow. See Understanding node-red context variables Click to rate this post! [Total: 3 Average: 5]Continue reading
The control UI node allows dynamic control of the dashboard. A typical use is for creating dynamic menus. A dashboard consists of tabs and groups. Dashboard nodes are placed in groups and groups are placed on tabs as shown in the diagram below: Click to rate this post! [Total: 4 Average: 5]Continue reading
Environmental variables are used on operating systems (Linux,Windows etc) to store user and system data. Environmental variables are stored as key value pairs of the form name=value. A common environmental variable on Linux and Windows is the use home directory. On windows this is HOMEPATH and on Linux HOME. Click to rate this post! [Total: 3 Average: 5]Continue reading
The chart node is used to display input data in various chart forms.(line, pie, bar etc).
The input data is usually time based but doesn’t need to be.
The input data can be real time or inserted from a database or log fileContinue reading