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BLE for environmental conditions

Written by
Lucas Cardon
Sales Engineer

In supply chain and logistics you often need extra data besides location. Amongst our customers and in the market in general, we notice an increasing demand from companies to track environmental conditions like temperature or humidity. To come up with the most reliable and cost-effective solution, we decided to couple existing sensors with our asset tracking solution via Bluetooth Low Energy (BLE). In this article, we discuss why we chose to integrate BLE in our product from the start and what we can achieve with it now in terms of environmental sensing. 

The igniter: Bluetooth Low Energy

Bluetooth is everywhere.

A wireless headphone.
An unplugged mouse.
A photo drop to a friends’ phone.

All enabled by Bluetooth. These applications sneaked into our daily lives like nothing.

Initially, Bluetooth aimed at enabling communication between a hands-free headset and a mobile phone. But we, consumers, experienced over the years that the applications of this short range data exchange technology boomed.

Besides the consumer world, it also stirred up the industrial world. At Sensolus, we chose to maximize the potential from Bluetooth and it’s low-power variant Bluetooth Low Energy (BLE) early on.

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Based upon the Bluetooth standard, Bluetooth Low Energy (BLE) is developed specifically for low-power consumption and smaller data rates. A perfect companion for products that are able to operate with small batteries for extended periods of time. In the case of Sensolus, a perfect fit with our low-power trackers.

Starting the fire: Low-power is in our DNA

Since 2016, we at Sensolus use BLE as one of the main geolocation technologies in our trackers, next to GPS and WiFi. Integrating BLE into our product was a very conscious choice at the time. We didn’t want to limit ourselves to outdoor geolocation only.

Supply chain and logistics processes contain several stages at which indoor location is crucial. For example, when manufacturing a plane at an indoor site or tracking rental equipment used indoors.

“Besides the argument of indoor geolocation, we also wanted to guarantee a several year battery lifetime for our trackers.”

For indoor geolocation, GPS is not an option and not every industrial site has access to WiFi. That’s why indoor geolocation starts with installing BLE beacons on fixed locations. These beacons constantly emit a BLE signal – subtly screaming ‘I’m here. I’m here’. As soon as our tracker picks up the BLE signal, its’ location is known. All of this consuming very little energy.

Besides the argument of indoor geolocation, we also wanted to guarantee a several year battery lifetime for our trackers. Combining several geolocation technologies helped us achieve a 5 year battery lifetime.

Spreading like wildfire: Getting specific process data

The third generation of our trackers, SNT3, is a perfect fit for industrial use cases and works seamlessly with our cloud platform. However, I do get a lot of questions from customers who require other data besides location. To tackle this, we upgraded our SNT3 tracker. It can now communicate with other existing environmental sensors.

The technology used for this communication is – surprise, surprise – BLE.

Adding already existing sensors instead of adding extra sensors to SNT3 itself is a well-considered choice. Hardware changes are expensive and different use cases require different sensors. Building one device that covers all possible use cases will never be cost-efficient.

“Coupling existing sensors with our tracker via BLE is the most reliable, cost-effective way to help our customers gather the needed process data.”

For us, it is only logical to interact with existing reliable third-party sensors. First of all since communicating with these sensors over BLE has a minor impact on battery consumption. Secondly, it makes it possible to expand the range of compliant sensors quickly without hardware changes on our side needed.


In short, coupling existing sensors with our tracker via BLE is the most reliable and cost-effective way to help our customers gather the process data they need.

By road and boat: A customer case about temperature monitoring of food shipment

I’ll illustrate what we just discussed with a customer case. This particular customer manages a large container pool. Since the containers travel over sea, road and rail the company decided to equip the containers with SNT3 trackers to monitor their location.

On top of location tracking, the customer came to me with the question to monitor temperature conditions in the containers used for food transport. One day, the shipment contains glucose. The next day, it can be cacao butter. All these products require stay within a specific temperature range during transport. This is regulated by a cooling or heating system.

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Before using our solution, temperature was read out manually by an employee checking the display  of the temperature sensor. This is time consuming and prone to error. With internet-connected sensor and BLE, you can eliminate this risk.

“This customer wants to monitor temperature of container content during transport over sea, road, and rail.”

We started installing a temperature sensor with a probe inside the container walls. It’s located close enough to the SNT3 tracker on the outside to communicate. In this case, the customer wanted to monitor two things related to temperature:

  • Temperature during the entire transport;
  • and he wants to be notified when a certain temperature threshold is exceeded.

Therefore, our product offers both continuous temperature monitoring and trigger-based notifications.

One challenge we had, was configuring the temperature sensor specifically for this use case. Glucose needs another temperature threshold than cacao butter. How do we solve this? The configuration of our trackers can be changed remotely, by you, sitting at your desk. Because of BLE, the customer is able to adapt the configuration per shipment.

“The configuration of our trackers can be changed remotely, by you, sitting at your desk.”

To save battery power and message budget when the containers travel overseas, we make sure intervals in which measurements are recorded are long enough.

Another challenge you come across working with LPWAN is network coverage. As you can imagine, at open sea, there is no network coverage. No network coverage means no temperature measurements.

We solve this with Data Recovery, our patented solution that recovers all data you could lose due to a lack of network coverage. Additionally, you can check the data from the extra sensor with your smartphone.

We received a lot of positive feedback on this case since we’ve shown the customer our solution is perfectly able to adjust to specific use case needs.

Getting a firm grip on your supply chain

In supply chain, environmental sensing helps you get a grip on all the processes involved. Reading out data manually is not only costly but also prone to error. Connected sensors are the simplest and most reliable alternative.

Several customers of us obtain all the process data they need by coupling our SNT3 tracker with other wireless external sensors. They receive this data without installing additional infrastructure or compromising on battery lifetime of the tracker.

What do measure at the moment?

  • Temperature
  • Humidity
  • Contact
  • Orientation

You can choose to couple only one external sensor to our tracker or you can couple multiple sensors, depending on your needs. If you need other environmental data to optimize your processes, let us know, we’ll have a look at how we can help.

More information? Contact us to discuss your use case more in-depth.