Mexican Highschoolers Launch 30 High Altitude Balloons

No matter whether you call them “picosatellites” or “high altitude balloons” or “spaceblimps”, launching your own electronics package into the air, collecting some high-altitude photos and data, and then picking the thing back up is a lot of fun. It’s also educational and inspirational. We’re guessing that 264 students from 30 high schools in Aguascalientes Mexico have new background screens on their laptops today thanks to the CatSat program (translated here by robots, and there’s also a video to check out below).

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Building A LoRa PHY With SDR

The Internet of Things is terrible when it’s your toaster. The real fun happens when you have hundreds or thousands of sensors sending data back to a base station every day. That requires low power, and that means LPWAN, the Low Power Wide Area Network.

There are a lot of options for LPWAN, but few are a perfect fit. LoRa is one of the rare exceptions, offering years of operation on a single AA cell, and range measured in miles. Layers two and three of LoRa are available as public documentation, but until now layer one has been patented and proprietary. At the GNU Radio Conference, [Matt Knight] gave a talk on reverse engineering the LoRa PHY with a software defined radio. Now, LoRa is open to everyone, and anyone can decode the chirps transmitted from these tiny, low power devices.

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Hacking The Internet Of Things: Decoding LoRa

Getting software-defined radio (SDR) tools into the hands of the community has been great for the development and decoding of previously-cryptic, if not encrypted, radio signals the world over. As soon as there’s a new protocol or modulation method, it’s in everyone’s sights. A lot of people have been working on LoRa, and [bertrik] at RevSpace in The Hague has done some work of his own, and put together an amazing summary of the state of the art.

LoRa is a new(ish) modulation scheme for low-power radios. It’s patented, so there’s some information about it available. But it’s also proprietary, meaning that you need a license to produce a radio that uses the encoding. In keeping with today’s buzzwords, LoRa is marketed as a wide area network for the internet of things. HopeRF makes a LoRa module that’s fairly affordable, and naturally [bertrik] has already written an Arduino library for using it.

So with a LoRa radio in hand, and a $15 RTL-SDR dongle connected to a laptop, [bertrik] got some captures, converted the FM-modulated chirps down to audio, and did a bunch of hand analysis. He confirmed that an existing plugins for sdrangelove did (mostly) what they should, and he wrote it all up, complete with a fantastic set of links.

There’s more work to be done, so if you’re interested in hacking on LoRa, or just having a look under the hood of this new modulation scheme, you’ve now got a great starting place.

The Future Of The Internet Of Things

When buying anything, you’re going to have a choice: good, fast, or cheap. Pick any two. A plumber will fix a drain good and fast, but it won’t be cheap. The skeezy guy you can call will fix a drain fast and cheap, but it won’t be good.

Such it is with radios. You can have long-range (good), high bandwidth (fast), or a low price (cheap). Pick any two. The Internet of Things demands a cheap, long-range radio module, but until now this really hasn’t existed. At Electronica last week, Microchip demoed their IoT solution, the LoRa. This module has a 15km (rural) or ~3km (heavy urban) range, works for a year on two AAA batteries, and is very cheap. Bandwidth? That’s crap, but you’re not streaming videos to your shoe.

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