Luos Web App: Alpha Version

April 15, 2022 · 3 min read

Architect @ Luos

Introduction

Who hasn’t struggled to install lousy software to run a camera, a printer, or any other device?

We all made it many times in the past years. Each of these programs answered a particular problem, from a simple update tool to a way to interact with you.

With the Luos engine capabilities, we can quickly provide all those features and many more without any installation!

Our path to achieving it wasn’t straightforward, so we will tell you how we achieved it...

Early stages

Gate

With our first try to connect embedded systems with a Javascript app, we based our development on the Web Serial API, a “living document” described by the W3C Incubator Community Group (WICG).

This normative-like document is near the Web Bluetooth API and Web USB API, among other things. This promises us great compatibility if it works fine!

On the other side, we developed an application service called Gate, which was intended to convert the Luos “generic software representation” into a JSON format.

The main advantages of the Gate were:

The simplicity of communicating with external systems.
The ability to act remotely on a system.

But it came with drawbacks. Here are some of them:

Our conversion layer takes the number of resources (CPU and memory).
The maintainability of two APIs for the same features (the internal one and the JSON one).

Sniffer 👃

In the second iteration of our connectivity between a Javascript app and an embedded system, we worked on the way to gather all the messages emitted into a Luos network and then transmit them to our app.

To do that, we created a tool called Sniffer. The Sniffer tool came with a new communication protocol closer to the embedded one but also with drawbacks, and one of them was the design itself; a Sniffer can’t act on the embedded system!

The solution 📐

Our third iteration came naturally a few times after as an Inspector. This solution gave the Luos web app the advantages of both the Gate and the Sniffer, without their drawbacks.

Our early works weren’t wasted, and we reused our firsts concepts! The high-level communication layer from our work with the Gate was the same, and we also reused most of our communication protocol from the Sniffer.

High-level communication layer

This part is about the implementation of the Web Serial API. This API gives us the ability to:

Get the list of available serial ports to communicate with.
Open/close the serial connection stream.
Read/write data on the stream.
Handle errors.

Protocol

We use the same protocol as the Luos engine embedded systems to read and write data.

(1) Illustration of the exchange of data between Luos and Luos Engine

As you can see in figure 1, the data is encapsulated in a “Luos Frame” described as:

Preamble: Detection of the start of a frame.
Target: Targeted node ID of the message.
Mode: Broadcast or targeted.
Source: Source of the message.
Size: Size of the data transmitted.
Data: The data we want to send.

Front-end 🌈

Now that we have set up this new way to communicate with the embedded world, the next step will be to give our users all the features implemented all over the years in Luos engine from a web perspective.

The first feature we decided to implement is the network topology. This feature is a graphical representation of the Luos routing table.

We first get the list of the nodes and services in our network. Then we query each service of each node to get their properties like their type (Motor, Led, Gate, ...), their firmware revision, and their memory statistics.

Illustration of the routing table data