I don&#x27;t know what they used for this project, but I have built similar things with the recently-released Particle Electron that I got on Kickstarter, though now I believe it&#x27;s released widely. Works really great, I was using the Spark Core before, same company and concept but with wifi instead of cellular.<p><a href="https:&#x2F;&#x2F;www.particle.io&#x2F;cellular" rel="nofollow">https:&#x2F;&#x2F;www.particle.io&#x2F;cellular</a>