Control your Raspberry Pi GPIOs from Arduino Cloud using Node-RED

Push Button

Diode Led Red 5mm

Breadboard 100x160

Raspberry Pi (Any Model)

Arduino IoT Cloud

<html><body>This project shows how to interact with the Raspberry Pi GPIOs from a dashboard created using Arduino Cloud with an application programmed in Node-RED. It can serve as an example to create your own applications that require access to RPI GPIOs and that can be ultimately controlled using a dashboard. <h3>The setup</h3>In this project I have used a Raspberry Pi 5 connected to an LED and a push button, both inserted in a breadboard. This is the diagram <figure><img src="https://projects.arduinocontent.cc/0d88cc48-51b2-4db3-b3f6-3bacd5dd507a.png"/><figcaption>Raspberry Pi GPIO setup diagram</figcaption></figure><blockquote>Note: This project should work with any Raspberry Pi version and actually with any Linux-based machine that supports libgpiod. Please, leave your comments if it does not work with your board in order to review it. </blockquote><h3>How to create your project</h3>The process to use this project is very straighforward: <ol><li>Create the Device and Thing in the Arduino Cloud and get the Arduino Cloud API Key </li><li>Install Node-RED and required nodes </li><li>Develop the Node-RED application </li><li>Create the Arduino Cloud dashboard </li><li>Test everything </li></ol><h3>1. Create the Device and Thing in the Arduino Cloud</h3><blockquote>Note: Before getting started, make sure that you have an Arduino Cloud account </blockquote>Create the Device Go to the <a href="https://app.arduino.cc/devices">Devices </a>section of the Arduino IoT Cloud and click on + DEVICE . Select " Any Device" and follow the instructions on the wizard. <blockquote>Note: Save your <code class="code">Device ID </code>and <code class="code">Secret Key </code>as they will be used in your python code. </blockquote>Create the Thing In your recently created device page, go to the Associated Thing section, click on " Create Thing" and rename it. <blockquote>Note: You can also create the Thing from the Things list and associate it later. </blockquote>Create the Variables Add the variables by clicking on the ADD button. At the end of the process, your list of variables should look like this. <figure><img src="https://projects.arduinocontent.cc/2d16bb57-911c-4ee2-a6f8-754be3bad4c8.png"/><figcaption>Arduino Cloud: Thing variables</figcaption></figure>Get an Arduino Cloud API key The process to get an Arduino Cloud API key is very straightforward: 1. Go to <a href="https://cloud.arduino.cc/home/api-keys">https://cloud.arduino.cc/home/api-keys </a>. 2. Click on CREATE API KEY and enter a name. 3. Note down the <code class="code">Client ID </code>and <code class="code">Client Secret </code>or download the PDF. We will use these credentials in the Node-RED node later. <h3>2. Install Node-RED and required nodes</h3>How to install Node-RED There are many ways to install Node-RED in a Raspberry Pi or any other machine. Typically, you can use: docker, snap, apt, native node.js installation. The tricky point is that we want our Node-RED instance to have access to the GPIOs and host system. This can be achieved with all the installation methods but for most of them it is quite difficult to achieve and many conflicts and issues need to be solved. So, the easiest and recommended way in this project would be to do a native installation using NPM. These are the instructions: 1. Node-RED Installation Install Node-RED with the following command <pre>sudo npm install -g --unsafe-perm node-red </pre>2. Manage the service There are many tools that can be used to manage the service, but I recommend using <code class="code">pm2 </code>to manage the service and make it start on boot. Install pm2 <pre>sudo npm install -g pm2 </pre>Edit the <code class="code">pm2.json </code>file and set the full path to your <code class="code">gpio-basic </code>folder <pre>{ </pre><pre>	 "apps": [ </pre><pre>	 { </pre><pre>	 "name": "node-red", </pre><pre>	 "script": "&lt;FULL_PATH_TO_YOUR FOLDER&gt;/pm2-node-red-start.sh" </pre><pre>	 } </pre><pre>	 ] </pre><pre>} </pre>Launch the service, save it and enable pm2 to start on boot: <pre>sudo pm2 start pm2.json </pre><pre>sudo pm2 save </pre><pre>sudo env PATH=$PATH:/usr/bin $(which pm2) startup systemd </pre>The service will be launched automatically on boot. You can manually start or stop the service with <code class="code">sudo pm2 start node-red </code>or <code class="code">sudo pm2 stop node-red </code>. Open Node-RED Open a browser a introduce the URL: <code class="code">http://&lt;IP_ADDRESS&gt;:1880 </code>, replacing <code class="code">&lt;IP_ADDRESS&gt; </code>with the IP Address of your Raspberry Pi. Your Node-RED environment will be opened. If everything was properly configured, you should see the flow <figure><img src="https://projects.arduinocontent.cc/41ccb365-b21d-4218-9374-395cde48050d.png"/><figcaption>Node-RED flow</figcaption></figure><blockquote>Note: If you can't see the flow and there's just an empty screen, you can either review the configuration (maybe the folder is not set properly) or you could also import the flow.json pasting the content directly using Menu--&gt;Import </blockquote>Install the required nodes The first time, you will probably get some messages indicating that there are nodes missing. It is because the application requires the following nodes: <ol><li>node-red-contrib-libgpiod : The nodes needed to interact with the GPIOs </li><li>@arduino/node-red-contrib-arduino-iot-cloud : The nodes to communicate with Arduino Cloud </li><li>node-red-contrib-cpu : I have used this node to generate an integer value that is sent to the Cloud. In this case I send the CPU load. </li></ol>In order to install the nodes, you just have to click on Menu--&gt;Manage Palette on the menu. Then go to the Install tab, search for the modules listed above and install them. <h3>3. Develop your Node-RED application</h3>If everything worked correctly, you should see the picture shown above. Now, it's time to configure the nodes. Configure the Arduino Cloud nodes First, let's configure the Arduino Cloud nodes. For each node, you have to do the following: 1. Select the Connection <blockquote>Note: The first time, you will have to set up the Connection and introduce the API secrets <code class="code">Client ID </code>and <code class="code">Client Secret </code>. </blockquote>2. Select the <code class="code">Thing </code>from the dropdown menu 3. Select the <code class="code">Property </code>(the variable) from the dropdown menu 4. Check the <code class="code">Send as device </code>box 5. Select the <code class="code">Device </code>from the dropdown menu <figure><img src="https://projects.arduinocontent.cc/038d0988-55c9-42cc-aec5-04984027dd04.png"/><figcaption>Configure the Arduino Cloud node</figcaption></figure><figure><img src="https://projects.arduinocontent.cc/614a5dcd-00f9-4a71-b9fc-398051e5155f.png"/><figcaption>Configure de Arduino Cloud connection</figcaption></figure>As a reference, you can see the full process in action for one node in the <a href="https://github.com/dbduino-prjs/rpi-arduino-cloud/blob/master/assets/RPI-GPIO-Basic-Node-RED-Cloud_Config.gif">animated GIF </a>in the github project. Configure the GPIO nodes First, let's configure the GPIO IN node. Double click on the node and set: <ol><li>Device --&gt; Set your <code class="code">gpiochipX </code>(gpiochip4 in the example) </li><li>Type: Digital pin </li><li>Pin --&gt; Set your pin number </li><figure><img src="https://projects.arduinocontent.cc/c006beb8-efb2-4c56-b01e-2287f4eee491.png"/><figcaption>Digital IN configuration</figcaption></figure>Next, let's configure the GPIO OUT node. Double click on the node and set:</ol><ol><li>Device --&gt; Set your <code class="code">gpiochipX </code>(gpiochip4 in the example) </li><li>Type: Digital (0/1) </li><li>Pin --&gt; Set your pin number </li></ol><figure><img src="https://projects.arduinocontent.cc/27d4e78f-a882-49b5-9b97-cca01c69a6b1.png"/><figcaption>Digital OUT configuration</figcaption></figure>Deploy Deploy the flow by clicking on the Deploy button on the top-right corner. <h3>4. Create the Arduino Cloud dashboard</h3>The dashboard that we are going to build will look like this <figure><img src="https://projects.arduinocontent.cc/22c5f020-2f37-4ed5-9bf2-19a1a5e3903b.png"/><figcaption>GPIO Basic Dashboard</figcaption></figure>There are 2 ways to create the dashboard: 1. Create it manually. Replicate the one shown above following the instructions in <a href="https://docs.arduino.cc/arduino-cloud/cloud-interface/dashboard-widgets/">this guide </a>. <ol><li>The LED widgets should be linked to the variable <code class="code">led </code></li><li>The Value widgets should be linked to the variable <code class="code">test_value </code></li><li>The Button widgets should be linked to the variable <code class="code">button </code></li></ol>2. Clone the one provided by this tutorial following the instructions in this <a href="https://github.com/dbduino-prjs/rpi-arduino-cloud/blob/master/js/gpio-basic/README.md#clone-the-dashboard-using-cloud-cli">Annex </a>of the github project. <h3>5. Test everything</h3>You should now see the following: <ol><li>Every time push the physical button, the button widget should be updated </li><li>Every time you change the LED widget in the dashboard, the physical LED should switch to ON or OFF </li><li>The value of <code class="code">test_value </code>should reflect the Raspberry PI CPU load updated every 5s, and you can see the evolution on the dashboard </li></ol>Enjoy! </body></html>