What is Node-RED and how to use it on Raspberry Pi

What is Node-RED?

Node-RED is a flow-based development tool that allows you to connect devices and services visually through a web browser.

Originally created by IBM, Node-RED is designed to facilitate the integration of IoT services and automation through a drag-and-drop graphical interface.

Node-RED allows us to create our “programs” through visual workflows using a very simple graphical interface. This makes it easier to integrate different services and devices without the need to write extensive code.

Main features of Node-RED,

Installing Node-RED on Raspberry Pi

To install Node-RED on our Raspberry Pi, we follow these steps. As always, it is first recommended to update the existing packages on the system.

Then, we install Node-RED using the official installation script provided by the project. Run the following command to download and install Node-RED:

This script will take care of installing Node.js (if not already installed) and Node-RED on our Raspberry Pi.

To make Node-RED start automatically when the Raspberry Pi boots, run the following command:

Finally, we can start Node-RED with the following command:

Basic Use of Node-RED

Once installed, you can access the Node-RED user interface from a web browser at the address http://<IP-of-your-Raspberry-Pi>:1880. This is where you will build your workflows.

To create a workflow in node-red, we simply drag the nodes we want to use from the node palette on the left side of the screen and connect them together.

Then, we can configure each node to fit our specific needs. To do this, we click on it, and the available options will appear in the palette on the right.

For example, if we want to read the value of a sensor and publish it on a social network, we could drag a sensor node, a social media publishing node, and connect them together.

Then, we would configure the sensor node to read the specific sensor we are using and the social media publishing node to connect to our Twitter or Facebook account.

Finally, once we have created our workflow we can deploy it (run it). To do this, we click the “Deploy” button to implement it and start processing data.

We can also access the processed data and visualize it in graphs and tables using the visualization nodes available in the node palette.

Workflow Example

Let’s create a simple flow that injects a message and displays it in the debug console:

This flow simply uses an Inject node to generate text that we send to Debug for visualization. By default, if we don’t change the configuration, the Inject mode simply generates a Timestamp (the current time).

Now we turn on the Debug tab and click the “Deploy” button to deploy the flow. When we activate the “TimeStamp” node (by clicking the little blue square to its left) we will see the message appear in the Debug tab.

Device Integration

Node-RED is very well integrated with Raspberry PI as it can directly access its GPIO to perform readings or generate outputs.

To do this, we must first install the node library Raspberry Pi GPIO to control the GPIO pins of the Raspberry Pi:

• Open the node menu and search for “node-red-node-pi-gpio”
• Click “Install” to add this node to your Node-RED instance

Once installed.

Now, when you send a message from the “Inject” node, the GPIO 17 pin will change state, turning an LED connected to it on or off.