Semtech SX1272 (LoRa), A Review

by JP Norair on 06 Dec 2016

in Uncategorized

Much has already been said about the LoRa PHY, but perhaps less-so about the transceivers you must select if you wish to implement LoRa.  All blog articles about LoRa tend to focus on the PHY and not the embedded systems perspective.  I will evaluate both aspects.

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As some of you may know, HayTag uses a solar energy harvesting power system.  It also uses a SPIRIT1 transceiver, which has a DC-DC converter built-in, meaning that the HayTag hardware includes a total of two DC-DC converters: a boost converter in the solar battery charger, and a buck converter in the SPIRIT1.  LoRa and SigFox radios do not include integrated DC-DC, but many of the new low power MCUs (TI MSP432, Atmel SAM L, even TI CC13xx), so there’s a good chance we will see designs coming out with LoRa radios and these microcontrollers.  Here’s my advice on how to practically address the problem.

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Internet 1974 vs. IoT 2011

November 18, 2015

Just a slide I made a while ago, that shows why IP (Internet Protocol), and especially TCP philosophies might not be such a great idea for IoT.  The technology landscape has changed: There are billions of cheap devices now, vs. a few expensive systems then A $1 MCU has more computing power now than the […]

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Computer vs. Thing: a Philosophical Razor

May 26, 2015

There should be a simple distinction between a “thing” and a “computer,” in order to assist marketers who may be over-eagerly branding products for the “Internet of Things.”  The Internet of Computers already exists.  The Internet of Things is slowly emerging.  Therefore, I present a philosophic razor of three criteria with which, I believe, “thing” and […]

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Q&A on 2015 IoT Trends and Issues

May 14, 2015

I was solicited on Quora to answer some questions about IoT, and I decided to do it knowing well that I’d repost them here.  Here’s my take on a handful of questions related to contemporary (2015) IoT trends and issues.

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The C

April 18, 2015

You can’t kill the C, The C will live on. Ada tried to kill the C, But they failed, as they were smite to the ground. C++ tried to kill the C, But they failed, as they were stricken down to the ground. Java tried to kill the C, Ha ha ha ha ha ha […]

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Using HW RTC as an RTOS Timer

April 15, 2015

Let’s say you are writing a low-power embedded RTOS (maybe: OpenTag) and you need a tickless timer that can operate through the lowest power sleep stages of your MCU.  Some MCU designers were nice enough to provide a special timer for this purpose (e.g. STM32L0, STM32L4, EFM32).  Others did not —  the STM32L1 was the […]

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EAX Cryptography is Awesome

April 15, 2015

The short of it: EAX seems roundly superior to the CCM cryptography used by the likes of WiFi and ZigBee.  For years I have been investigating different approaches to cryptography in order to find ones suitable for Internet-of-Things applications. With IoT, you cannot guarantee that a device in the network has a lot of memory, […]

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LoRa as a PHY for DASH7

March 28, 2015

In 2013, Semtech released its SX127x “LoRa” wireless transceivers.  LoRa™ is of course short for “long range.”  LoRa uses CSS (Chirp Spread Spectrum) as a form of modulation, which improves its robustness in environments with lots of interference and also allows it to run at very low datarates without the normal tradeoffs of narrowband modulation. […]

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DASH7 Specification Draft 16

March 28, 2015

Here is the public release of the DASH7 Specification, Draft 16.  The specification is authored by Haystack Technologies, and it is published on indigresso.com with permission. If you are viewing this post on the blog homepage, use the “click to continue” link to download the spec.  

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