Publish JSON Data over MQTT with Node-Red

One of the the most common use scenarios for using JSON data is for combining data from multiple sources.
In this tutorial we will simulate a multi-sensor environment were we collect data from several sensors and publish it wusing MQTT on a single topic using JSON encoded Data.
The video also demonstrates how we can hold and delay publishing data while we combine it.
To accomplish this we use a fuction node and use the context object to store sensor values before we publish them.

Related Tutorials and Resources
Flow used in video
-
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Introduction to JSON
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Working With JSON Data in Node Red
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Creating a Simple Controllable MQTT Sensor With Node-Red
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The Node-Red Message Object for Beginners
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Create a Node Red Basic Flow - MQTT Subscribe Example
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How to Create a Node-Red MQTT Dashboard
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How to Store Data In Node Red Variables
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Receive JSON Data Over MQTT with Node-Red

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[loggerman]

Hi Steve, just wanted to say how clear and understandable your tutorials are; you have helped a great deal! Cheers, Adrian

[zhinadr]

You really helped me a lot, I watched almost all of your videos. Thank you.

[astrogerard]

Thanks for sharing and taking the time to make these useful tutorials.

[nurwardiahspian]

thanks for sharing..this is a very useful tutorials

[anamariadragulinescu]

The only node you have not opened (for the settings) was JSON....

[petersamoaa]

Hi, Thanks for your useful video
but just I need to ask you about thing.
suppose that I have Mosca broker on my local machine and send JSON data related to GPS position with the format
{ payload: __, context: { lat: __ lng: __ }, timestamp: __ }
and other Mqtt subscribe in this content.
can you illustrate this ?!