Glass-Link - The Platform

Hi there! Glass-Link is on its way! We are happy to share with you some of the early results we achieved with the Glass-Link network. In this article, we’re presenting the current platform, that powers our system.

The Network

As in many coordinated network architectures, Glass-Link as well uses the commonly known approach of connecting Nodes through a Gateway. The Gateway acts as a sort of access point in the network, allowing the Nodes to access the network and to communicate with the cloud application. In our current setup, we use Raspberry Pi 4 B as our base for the Gateway device.

The Gateway

You can see the Gateway with a standard 2.4G antenna in the above picture as well as the 2.4GHz RF module from Semtech waiting for assembly. In the development stage, we decided to go for off-the-shelf components for mainly two reasons.
• It speeds up the development process and also...
• guarantees good reliability and assumed performance of the selected parts.

Here’s a Gateway after assembling the RF module. As you can see the radio module takes very little space inside the case. We are currently working on a custom PCB that will support several RF chips from different vendors and a front-end Power Amplifier. More about it later.

Device connection

Ok, so we have the Gateway ready for powering up. Let’s connect the device to the router and power it up via the USB-C cable.

Wow! Nothing blew up - we can continue ;-) As you can see in the pictures, the Gateway is connected to the router via an Ethernet cable. This is one of the possibilities to put the Gateway online. Another way is a configuration of the WiFi over the built-in WiFi Access Point, but we won’t go through this setup in this example.

The Node

The second part of the network architecture is the Node. In the current development, we decided to go for ARM-Cortex M0+ based platform, as it has enough power to perform even complex tasks being an ultra-tiny device. On the other hand, it supports several interesting power-saving modes, that we are utilizing in order to extend the battery life of a Node.

Depicted you can see an example node connected to the RF module and a multifunction sensor from Bosh (bmp280). The Node is powered by two 1.5V AAA batteries.

The Node in this configuration can be powered either from the battery or through the USB-C cable.

The Platform Software

Now few words about the platform software. For the Gateway, we decided to go for Ubuntu OS.

Ubuntu Server has proven its reliability over many years now and we think it’s a great choice for many network-enabled applications. This particular deployment is already preconfigured and equipped with Glass-Link platform software. The platform software consists of several processes and services that are running in the background and continuously monitoring the RF network and cloud connectivity.

The platform software for the Node is our proprietary software designed and written specifically for Glass-Link. It supports the highest possible connection speed to/from the Semtech RF module.

PCBs for Gateway and Node

This bring us to the end of this blog article to conclude with first proof-of-concept tailored designs of PCBs for the Gateway and theNode.