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Turning Wired Connections Wireless

The Air Liquide Project

“Turning something wireless” has been the basis of our careers for over 20 years. We started with computers… turning PCs into Smartphones. Tech advances mean building wireless products is easier than ever. But if you don’t know where to start, it can be daunting. Luckily, our specialty is going from 0 to 1 – from nothing to something.

Our client, Air Liquide, wanted to explore wireless connectivity for their remote site gas monitoring. The business objectives were to reduce site installation cost and complexity. By moving to more modern wireless architecture, they can improve their operational efficiencies by introducing some edge (or near-edge) computing capabilities and open up doors for easy integrations with partners in the future.

Getting Started

I always like to cover how projects get started, from both the business and the technical side, mainly because I find it interesting when I read about how other people develop business! Our team is constantly building products for ourselves, for others or just for fun. We keep in touch with tons of manufacturers and suppliers. One of our component suppliers was chatting with their client, Air Liquide, about one of their visions and knew we could build them something quickly that would work.

It’s very typical for bigger businesses to outsource ideation and early development of ideas before they bring it internal into their organization. Big companies are constantly working on many early-stage ideas at once before finalizing their strategic plans.

From a technical perspective, starting this project was fairly routine. We always aim to keep it simple and flexible and avoid custom work until we’ve got a Proof of Concept up and running. One of their primary concerns was easy integration and installation with their existing system. Once we got our hands on their current wired solution, we did some technical research, drew up some plans and dug into our drawers to start building!

System Architecture and Design

When we’re talking about remote monitoring over large areas with many sensors distributed in that area, we go straight to LoRa as the first choice. LoRa offers long-range, low power options that are becoming more and more affordable for end nodes. Mesh technologies aren’t ideal here because mesh requires the nodes to be constantly on, which isn’t great for power consumption. Cellular options can quickly become expensive and operationally cumbersome to have a SIM in each sensor reporting very small amounts of data.

To make integrations easy in the future, using the LoRaWAN network here makes sense.

The LoRaWAN network uses a standardized communications protocol so that any deployed, available network in the area can direct sensor messages to the right spot in the cloud.

The architecture is IoT-based, where many gas-monitoring sensors in a location connect to one centralized gateway that pushes information into the cloud to be accessed through the Internet.


As always, we iterate on the design as we go. First, we used an NM180100 EVB we have onsite to build out the connection and work in an open space. We wired it up with an RS-232 Transceiver on the breadboard. This proved out the serial connection and communication and let us implement the firmware to run on the Ambiq Apollo3 ARM Cortex M4F processor. The code was written to send and receive ModBus commands over serial, essentially turning the NM180100 into the ModBus master.

Then, we started on the wireless connectivity. We connected the NM180100 wireless through LoRa using The Things Network (TTN). We verified that we could receive send commands all the way from TTN directly to the meter and receive responses, end-to-end.

Once the system was up and running, we focused on configuring a gateway to check the localized implementation. We chose a Multi-Tech MTCDT-247L because Air Liquide wanted to test on their own localized network first and be flexible to move to LoRaWAN. This gateway also runs Node-RED, which is a useful tool to quickly and easily write and deploy server-side programs.

Once the system was working in the big form, we moved on to making the design more compact and easy to install. We were still focusing on using off-the-shelf components here as we’re only making a small batch for testing. We chose the SparkFun LoRa Thing Plus ExpLoRaBLE board, since it also uses the NM180100 LoRa/BLE module and since we wrote most of our embedded software in Mbed, it was an easy choice. (Side note: you can learn more about our development of this board here!)

The other 2 small boards were the RS-232 Transceiver and a DC to DC power supply to allow for a single power source to run the unit. The gas meter took a power supply between 9V and 30V so we made our power supply selection based on suitability to that spec.

We wanted a small container that would be suitable for the installation environment. We found a cost-effective option that’s ~2”x3”x1.5”. We designed a simple tray to sit snugly in the box and hold the 3 boards, keeping the wires cleanly organized underneath it. We put a small 9V battery inside the box, connected to the power supply. The design was done so that either the battery could power unit and the gas meter, or the meter could power the unit.

We added an external antenna that connected to the uFL on the Sparkfun board. The exterior of the box just has an SMA connector so any 900 MHz regular SMA antenna can be easily swapped out.

Final Product Highlight

The final deliverable was a few units of the Proof of Concept design to use for demos and testing. The deployment area will be a tower with gateway at a high point in an urban setting and end node units will be in standard outdoor, urban and rural locations nearby.

For easy installation, it gets retrofit onto a meter by simply removing the cap, plugging in the connectors, putting the cap back on and then configuring their dashboard to identify that end node with the correct meter.


· Parts: electronics in tray, housing, antenna, battery

· Size: 2”x3”x1.5”

· Power inputs: 9V-30V

· LoRa/BLE wireless communications

· LoRa range: 5-7km conservatively, 10-15km in open air with line of sight

The Proof of Concept is built for future capability, the processor utilization is very low so it’s open to work in experimentation on edge processing and machine learning applications in the future.

The gateway provides a unified dashboard view of several remote sensors and provides it as a single virtual ModBus device for the Air Liquide team to use for operations, analytics, maintenance planning and any other systems that can benefit form the remote monitoring.

What’s Next?

For this project, we’ve done remote demos and shipped the PoCs to Air Liquide for them to install on-site and do a live demo showcasing the monitoring solution.

Next is to make it a full custom design that’s smaller, cost effective and scalable to manufacture. The target would be to make it fit right inside the meter itself with the antenna being run externally. The new design will be able to power the device from 5V-30V (wider range). The majority of the work will be on the communications side to beef up the features that are there and to enable some edge computing decisions.

Wrap Up

We spend a lot of time talking to clients and partners about tech decisions.

Something that has become much more prevalent lately is the fact that companies are growing tired of buying solutions that come with recurring service costs to be able to access their own data.

Especially those with lack of customization. We’re seeing more and more companies wanting to move towards a model where they have full access and full control of their data.

The freedom of having unlimited access to your own data without needing to pay “subscription rates” was a key driver of this project. It seems like the B2B SaaS model that investors love may be becoming tiring to their end customers. So, when the corporate budget allows, there is significant value in building a custom solution and very few barriers with the right design partner.


JTDC is a group of Electronics Enthusiasts that help people build tech-inspired solutions, focused on designing IoT products that make sense for your business. If you have a project you’ve been thinking about for your business but don’t know where to start, talk to us about our processes to learn how we can help.

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