Hi and Welcome to Steve’s Internet Guide.

The first wave of the Internet involved connecting people to each other and people to information.

The next wave of the Internet will involve connecting the physical world to the Internet, and machines to each other (M2M – Machine to machine). See An Introduction to IOT

How will these devices be managed and monitored? What will happen to the data.

IOT MQTT and Node-Red

Node-Red is a flow based programming tool that is being used for monitoring and managing IOT devices and systems.

Node-Red makes it easy to create IOT systems with little or no programming knowledge using a web browser interface and could easily become the WordPress of IOT.

MQTT is also fast becoming the de facto IOT messaging protocol and having a working knowledge ot this protocol will be essential for building IOT systems.

This site will focus on Node-Red and building IOT systems using it.
If you have any questions please ask

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I have developed a few flows for third parties that have mainly involved decoding Modbus data.

However I have never used Modbus in a live environment and needed to get familiar with the basics in order to develop and test these flows.

Fortunately the people I worked with had a very good understanding of Modbus, but not of node-red, JavaScript and MQTT

These are my working notes from my efforts to create these flows and in particular an MQTT to Modbus bridge.

If you are new to Modbus you may find them useful. (more…)

The MQTT protocol allows messages with a maximum size of 268435455 bytes approx 260MB.

This is obviously a very large message size and one that most brokers,especially public brokers, will restrict. (more…)

Often you want your flow to start with known conditions.

For example you may have a flow that records various sensors and have alarms set when the sensors exceed a given value.

As an example you may want to trigger an alarm when the temperature falls below 3 degrees or exceeds 30 degrees Centigrade. (more…)

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: (more…)

The MQTT CONNECT and response messages (CONNACK) have been greatly enhanced in MQTTv5 with the addition of the properties field.

The properties field allows for a large increase in the information that can be exchanged between client and server on connection establishment compared to MQTT v3.1.1.

For example it is now possible to restrict the maximum message size the server will send to the client by telling the server what size the client will accept.

The purpose of this tutorial is to provide an overview of the CONNECT message in MQTTv5 and do a quick Comparison with MQTT v3.11. (more…)