![[Tutorial] Realtime interfaces and physical spaces — with WebSockets, Next.js and IoT](https://assets-global.website-files.com/5ba3150a54f21cfe3f02b031/60e833e7090062c1f6d6ea97_gravio-article-demo-4mb.gif)
This article is about combining various technologies and concepts to create a physical user experience using Gravio and a custom Next.js (a React.js framework) setup, with WebSockets and HTTP APIs. Links to all the code and configuration you’d need to create the same setup are included below.
By the way, our quick definition of IoT (Internet of Things) is about connecting a Thing, like an electronic button or temperature sensor, to the network (or Internet) — enabling all connected Things to communicate, and therefore enabling new forms of interactivity, learning, safety and so on.
Create a simple experience for capturing and responding to user feedback within a physical space.
It might look and work something like this:
Due to time constraints this prototype had to be built quickly, with the intent to create the simplest, most direct and real-time solution for getting the information from the devices to a display. To help support that effort, we’d ideally keep the number of moving parts to a minimum too.
Also being a prototype, we could test and take learnings from a real environment that could inform any production build thinking down the line.
Technically, there are various ways to approach a project like this, but given the limited time, etc — our focus needed to be on the experience. So we prioritised using technologies that we were familiar with to be the most productive.
And for us that meant using web technologies for the visual side (a web app), so given this choice and the real-time requirement, we’d also use WebSockets for the real-time updates.
At a high level, we saw the solution having three core components:
1. An IoT Edge environment
That provides the user with:
2. A Middle layer
As mentioned, we chose to use web technologies to speed up the prototype UI build, and that meant using WebSockets for the realtime requirement.
So a Middle layer was needed to transform and pass the data from the Edge to the web app, and because Gravio is flexible and offers different ways to pass the data, we saw two obvious options for the Middle layer (see below).
3. A web-based User Interface / Front end — the UI
This consumes the WebSocket updates and then provides the user with feedback — shown on the visual display — to close the loop.
In IoT land, MQTT is the de-facto protocol for IoT-based messaging. So our initial thought was to use it for this prototype too, however:
So we considered a custom approach too…
This was essentially a combination of:
We chose the custom route for the Middle layer to work in hand with Gravio, and although this approach might seem like it had more unknowns, ultimately it was the tighter level of control and fewer moving parts that would allow us to be more flexible and therefore more creative with the final experience.
For the custom Middle layer we decided to use Next.js, and were even able to combine both the Middle layer features (HTTP and WebSocket servers) and the UI into just one Next.js project by using: a custom server, referencing the Next.js Express example, and some other WebSocket and Node.js references — see code for final solution:
https://github.com/dfjs/realtime-physical-spaces
Note: You can review the code and setup in more detail to get a deeper understanding, where there are comments to outline what’s going on.
Let’s get started!
Note: we won’t cover installing and setting up Gravio in this article, but you can refer to that for macOS here and for Windows here.
This is the rough flow of activity that we’ll need to implement to support the desired experience:
First let’s setup the physical (or Edge) environment side using Gravio Studio — remember, you’ll need the two buttons we’re using here to create the same setup.
1. In Gravio Studio, starting in the Device tab, if you don’t already have an Area created, create an Area called Sensors, using the Add Area button in the main toolbar
1.1 Then add two Layers called ‘Yes’ and ‘No’ with ‘Aqara-Single Button’ as their types
Your Layers list should looks like this:
2. Next, you’ll need to pair two Buttons — see the pairing reference here
Note: from Gravio 4.3 these buttons should automatically be assigned to the layers you created in step 1.
3. Next open the Actions modal, and create a new Action by click the ‘+’ button in the top right — (Action Editor reference here)
3.1 In the create Action modal, name the new Action ‘ResponseYes’
3.2 In the new ResponseYes Action window, click Add Step, select the Network tab, select the HTTP Request step type, and click Add
3.3 Select the new HTTP Request step and in the URL field we’ll enter the HTTP server address request endpoint (we’ll assume it’s your local machine here): http://127.0.0.1/buttons/yes
Now your action should look something like this — simple:
Next we’ll create the ResponseNo action.
4. Close the ResponseYes action, where you’ll now be in the Actions view. Click (to select) the ResponseYes action and click the Duplicate selected Action button in the Toolbar:
4.1 In the Duplicate Action modal, enter ResponseNo for the action name, then click OK
4.2 You’ll be taken back to the Actions view, open the new ResponseNo action, select the HTTP Request step, and amend the URL field in the HTTP request to: http://127.0.0.1/buttons/no
Your ResponseNo action should now look something like this:
4.3 Now close the Action, and close the Actions view.
You should now have two actions that will make an HTTP request when they’re triggered, which we’ll setup next
5. Go to the Trigger tab, and click the Add new Trigger button, which looks like this:
5.1 In the New Trigger modal, enter the name PushYesButton
5.2 Then within the Conditions tab, select Sensors from the Area dropdown, and in the Key Layer dropdown, select Yes (your Yes button device)
5.3 Then to the right of the Physical Device ID field, click the ‘+’ button, which should then show you a button, tick the check box — and make sure the Button press dropdown is Single press (the default)
Your new trigger should now look like this:
5.4 Now select the Action tab, and for the Action dropdown, select ResponseYes, then click Add (this will create and close the Trigger)
6. Now follow the same steps for creating the PushYesButton trigger, but for the PushNoButton equivalent, your new trigger should look like this:
6.1 In the the Action tab, and for the Action dropdown, select ResponseNo, then click Add — this will create and close the Trigger
Your Gravio Edge environment is now set up and ready to go!
Here are the steps to download, install and get the server running. We’ll go through what it’s doing and the key areas later.
Steps:
a) Git clone (or download the Zip) from https://github.com/dfjs/realtime-physical-spaces
b) From within the project folder, install the server (i.e. its dependencies)
c) Start the server
d) Check that it’s running correctly (it’ll say “Ready on…”)
Here are the steps above on the command line:
$ git clone https://github.com/dfjs/realtime-physical-spaces
$ cd realtime-physical-spaces
$ npm install
$ npm start
Ready on http://127.0.0.1:3000
Notes on the server: this server is built with prototyping in mind, and specifically for the scenario we have here, which both makes the code easier to understand and change, or adapt for your own use case.
We used a development machine to run the Edge environment (Gravio) and the Middle layer (Next.js, etc) and the Browser to show the UI. But if you wanted to put this out into the real world, you’d want to use something more suitable for that, and what we suggest below could be a good start.
For a setup that’s closer to real-world use — like our challenge illustration above — you’d likely use a large standalone display to make it visible and readable for customers.
For your computing device, you could use a Raspberry Pi with Ubuntu OS (64 bit) installed, plugged directly into and mounted behind the display.
With the Pi plugged into the display, you could run a browser with the web app in full screen mode (i.e. no browser chrome / ui) — a common approach in retail environments for example.
Finally, simply place (or stick!) the two physical buttons nearby, done!
This setup would create a seamless experience for your users to interact with, which you can monitor, analyse and tweak (then scale!) in the future.
This experience has a range of applications! Especially when you start introducing more devices, longer interactions, etc — like:
And more! This is the power of IoT — the ability to connect physical spaces and create connected experiences.
All with the benefit of flexible privacy setups, reduced data handling, and no external network dependencies, like the Cloud.
Looking for more info? Get in touch on Twitter or email info@gravio.com 👋
