Unlike terrestrial networks that cover only about 15% to 20% of the planet’s surface, satellite networks can cover almost the entire Earth’s surface without the need for infrastructure (communication towers, base stations, electricity, etc.). Satellite radio can send data from the Sahara, the Amazon, or Antarctica, so it covers the growing need for connectivity in isolated or inaccessible areas.
Satellite is one of the few radios that Libelium has not integrated yet. We decided to make a call for a student who carries out the state-of-the-art and integrates the Swarm radio hardware and firmware into the Libelium platform.
Raul Estremar answered our call. He is a student of Electronic Engineering at UNIZAR (University of Zaragoza) and when he saw the internship offer that Libelium launched for students of Telecommunications or Electronic Engineering degrees, he didn’t think twice. These internships would help him to develop his Final Degree Project, an essential step to receiving his degree.
The Swarm radio is very affordable due to its low cost and low battery consumption. In addition, it is very reliable and accessible: on their website, there is documentation on how to connect to their satellites. So Raúl started working on the Swarm module integration in Waspmote, Libelium’s OEM board.
Swarm satellites are Low Earth Orbit (LEO) satellites: they “float” at 500 km, or even less. This short distance to Earth means lower signal loss and less interference than other satellite systems, reducing power requirements and making them ideal for communication with low-power IoT devices such as Waspmote.
Raul studied the documentation shared by Swarm on how its satellites function and designed a library for Waspmote to send data and communicate with those satellites. Swarm Technologies has a constellation of about 150 nanosatellites in orbit. They are the smallest commercially operational satellites in space, with a size of only 11 cm.
Swarm has a web application that allows you to see the time slots in which the satellite will pass over the next few days, which allowed Raul to anticipate at what time it will be possible to transmit data from Waspmote.
The use case Raul has been working on is IoT for forest fire prevention and warning. Forests are often remote areas with little or no Internet coverage. To broadcast and receive an internet signal it is necessary to acquire, install and maintain an expensive communications infrastructure that, in case of fire, would be inoperative. Satellite communication then becomes the ideal option.
The risk of potential fire increases when the temperature exceeds 30 degrees Celsius, the wind exceeds 30 km/h, and the relative humidity is less than 30% on the same day. This is the so-called 30/30/30 rule. With Waspmote’s wide range of boards and sensors, it is easy to take these measurements. Raul used the BME280 sensor, which measures temperature and humidity, and a weather station on Waspmote’s Smart Agriculture board.
Once he had the electronics, he modified the program he had made from the library so that it could measure the sensor values and create a message containing all the data to be sent to the Swarm satellites when possible.
Then, implementing another function in the program measures the values, creates the message, and sends it. The information provided by the sensors is stored in the Swarm cloud. From there it is sent to the Libelium Cloud.
Of course, Raúl encountered various problems (such as finding a good solution for the antenna’s ground plane) that he had to overcome with expertise and with the support of his tutor at Libelium, Innovation Director Javier Solobera, to successfully develop his work. Even so, he is satisfied with the study and stresses: “I never imagined that space would be so accessible”.
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