How to Dynamically Update an Image on Your Node-RED Dashboard

Описание: Learn how to display and automatically update images in your `Node-RED` dashboard using `httpStatic` settings and template nodes.
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How to Dynamically Update an Image on Your Node-RED Dashboard

When working with Node-RED for various automation tasks, you might find the need to display images that update in real time. For instance, if you're performing object detection using a camera and the resultant image is updated and stored in the same directory, showing this live feed on your dashboard can enhance visibility and interaction. In this guide, we will explore a straightforward solution to accomplish this using Node-RED hosted on your Mac.

The Challenge

You have already set up an object detection system that updates an image at regular intervals. However, integrating this dynamic image feed into your Node-RED dashboard has proved to be challenging. The media node, which was a potential solution, didn't provide the real-time update you were looking for. Fret not! This guide will walk you through the steps necessary to update the displayed image whenever the source image changes.

Solution Overview

The solution consists of two main parts:

Setting httpStatic in the settings.js file.

Configuring the template node in Node-RED.

Let’s break down each step in detail.

1. Setting Up httpStatic

To allow Node-RED to serve your image files directly, you need to set the httpStatic variable in your settings. This variable instructs Node-RED where to look for your static files.

Steps to Set httpStatic

Locate the settings file: Navigate to the folder ~/.node-red and open the settings.js file.

Uncomment the httpStatic line: Find the line starting with httpStatic and uncomment it. Make sure to set the path of the directory where your images are stored, formatted as follows:

[[See Video to Reveal this Text or Code Snippet]]

Restart Node-RED: After making this change, you will need to restart Node-RED to apply the new settings.

This setup will allow Node-RED to serve files from the specified directory, acting as a root directory for images.

2. Setting Up the Template Node in Node-RED

Now that you have configured your static file serving, the next step is to create a mechanism that refreshes this image on your dashboard periodically.

Steps to Create a Template Node

Add a template node: Drag and drop a template node into your flow within Node-RED.

Insert the code: Use the following HTML and JavaScript code in your template node:

[[See Video to Reveal this Text or Code Snippet]]

Customize the Paths: Ensure that you replace "path to your image w.r.t. httpStatic" with the accurate path relative to your httpStatic directory.

Adjust Parameters: Feel free to change the dimensions, alignment, and refresh interval as per your requirements. The current setting, for instance, refreshes the image every 7 seconds.

Conclusion

By following these two main steps, you’ll be able to show an image on your Node-RED dashboard that updates dynamically, reflecting any changes every few seconds. This feature is especially useful for applications that involve real-time monitoring, like object detection feeds from cameras.

Give this a try, and enhance your Node-RED dashboard with live image feeds that keep you in sync with your automation tasks!