Node-RED: Lecture 6 – Example 6.7 Multiple inputs on a function node

Example 6.7 Multiple inputs on a function node

Function nodes in Node-RED were designed to process messages as single entities. However, in some cases your functions might depend on two separate data sources. There are many ways to handle these cases in Node RED. The following approach uses the context object in Node-RED and topics to let a function wait for several messages to arrive in order to return.… Read the rest

Node-RED: Lecture 6 – Example 6.3 Using context to generate rolling averages

Example 6.3 Using context to generate rolling averages

A special module called context, used to store data between function invocations, is available to function nodes. This can be useful when the function needs to retain state to do its processing. For example, in a typical Industrial IoT scenario, it may be necessary to compute the average value of a sensor’s data readings over a period of time.… Read the rest

Smart City standards: an overview

Making sense of Smart City standardization activities

Update: For a fuller discussion of Smart City technologies, including standards, read Smart City Technology Trends


Last year I was asked to write an article on Smart City standards for the IEEE standards magazine. This blog post was the basis for that article, but also acts as an evolving document as I update it as standards activities evolve.… Read the rest

Tutorial: Node-RED dashboards – creating your own UI widget II (using external charts)

Creating your own UI widget for a Node-RED dashboard using an external charting library

Node-RED’s dashboard nodes provide a comprehensive set of UI components for building basic dashboards suitable for the Internet of Things (IoT) – offering graphs, gauges, basic text as well as sliders and inputs. However, there will always be situations when you need something custom.… Read the rest

Tutorial: Node-RED dashboards – creating your own UI widget

Creating your own UI widget for a Node-RED dashboard

Node-RED’s dashboard nodes provide a comprehensive set of UI components for building basic dashboards suitable for the Internet of Things (IoT) – offering graphs, gauges, basic text as well as sliders and inputs. However, there will always be situations when you need something custom.… Read the rest

Tutorial: Node-RED dashboards – multiple lines on a chart

Showing multiple lines on a single chart in Node-RED

This simple tutorial explains how to display multiple lines on a Node-RED chart. We’ll be building on a previous example in our lecture series (Example 7.2 in lecture 7)

As discussed in that lecture, let’s set up a simple flow to generate a random number and display it on a chart.… Read the rest

Tutorial: SQLite and Node-RED

This tutorial will show you how to make use of an SQLite database using the litedb node on the FRED hosted Node-RED platform to create database tables and store data. Under the hood, the litedb node uses SQLite.  As a very lightweight relational database, SQLite does not need complex setup procedures, making it an ideal database management system to use for embedded systems and rapid prototyping.… Read the rest

Lecture 7: Node-Red dashboards (Part 3)

Example 7.3 Using a simple JavaScript chart library to build a custom dashboard

For our final example of building Dashboards and UIs we’ll use a generic technique we’ve experimented with before. That’s the web service approach that uses a http node to allow us to accept http requests and return web pages.… Read the rest

Lecture 7: Node-RED dashboard (Part2)

Example 7.2 Introduction to the UI nodes from node-red-dashboard


This second example uses the built in dashboard nodes that come with Node-RED. If you are using FRED, make sure you have selected this node set from the add/remove button in the management panel and that you aren’t using the old legacy-ui nodes.… Read the rest

Node-RED: Lecture 7 – Dashboards and UI techniques for Node-RED

In this lecture you will take a look at a few techniques to allow you to visualize data passing through flows. We’ll focus on three approaches, the use of a third party dashboard tool, FreeBoard (Part 1), using the default Dashboard UI nodes provided by default in Node-RED (Part 2) and a general technique using a standard JavaScript charting tool (Part 3).… Read the rest