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.
Continue readingUnderstanding and Using Buffers In Node and Node-Red
When data is read from a file or network it is read byte by byte into a data buffer. Data Buffers are temporary storage used for transferring data. To work with binary data we will need access to these buffers.
Continue readingWorking with JSON Data And JavaScript Objects in Node-Red
JSON is popular format for encoding data sent over the Internet, and also stored in files. In computing, JavaScript Object Notation (JSON) is an open-standard file format that uses human-readable text to transmit data objects consisting of attribute–value pairs and array data types (or any other serializable value). –wiki
Continue readingCreating and Using Client Certificates with MQTT and Mosquitto
Another popular way of authenticating clients is via client certificates and can be use as in addition or as an alternative to using user name and password authentication.
Continue readingUsing the Node Red Status Node
In Node red any node can report status information in the visual editor. The screen shot below shows the mqtt node. It shows a green circle to indicate that it is connected and the text connected underneath the node.
Continue readingMQTT and Raspberry Pi GPIO
The Raspberry Pi has 40 General purpose Input/output Pins (GPIO) that can be used for controlling external hardware. There are a number of add-on boards called hats which plug into these pins and provide various sensors. The most common one being the sense hat.
Continue readingNode-Red HTTP Request Node for Beginners
The node-red http request node is a core node and can be used for making http requests. It can be used for. Retrieving web pages from a website Making API Request Sending and receiving JSON data to a website or API. etc
Continue readingNode-Red MQTT Data and Topic Logger
This is a data and topic logger similar to the python data and topic loggers that can be used for logging MQTT data to log files either as a single file containing multiple topics or multiple files based on topic. It is controlled using a node-red dashboard making it much easier to use than the python loggers.
Continue readingSimple Python MQTT Topic Logger
The MQTT data logger logs data to all monitored topics to the same log files. If the data need to be split into topics then it will need to be done by the log analyser software.
Continue readingBeginners Guide to Data and Character Encoding
When I first starting working with computers everything was in ASCII ( American Standard Code for Information Interchange ) However today working with networking protocols and network programming you will come across a variety of data and character encoding schemes. In this tutorial we will look at basic encoding schemes used on computers and in the second part of the tutorial we look at how data is sent over a network.
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