

Comparing Low-Power Wireless Technologies (2011) - sekasi
http://www.digikey.com/en-US/articles/techzone/2011/aug/comparing-low-power-wireless-technologies

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chas
This is a few years old and leaves out 6LoWPAN[1], which wasn't yet
commercially viable. 6LoWPAN is based on the same 802.15.4 hardware that
ZigBee uses, but it has two significant advantages over ZigBee. First, it is
TCP/IP that works on microcontrollers, so embedded devices running the
protocol become first-class members of the internet with the addition of a
very inexpensive router[2] to the network. This means that sensor nodes and
embedded devices can seamlessly interoperate with traditional servers in a
distributed computing environment and many programming techniques can be
directly adapted.

Second, 6LoWPAN can be configured so that all nodes involved can sleep,
whereas ZigBee requires always-on routing nodes in order to produce a true
mesh. This means it isn't possible to use ZigBee to construct a mesh out of
fungible battery-powered devices, which is a big problem for many
applications.

If this interests you, there are a couple of very capable chips that have been
released recently that are ideal for use with 6LoWPAN, namely TI's CC2538 [3]
and Atmel's SAM R21 [4]. They both are supported by Contiki OS[5], which
provides network stacks for extremely resource-constrained devices. It has
been under development for ~10 years at this point as an open source
academic/hobby project but in the last couple of years it has become
significantly more professional and it is now used in many commercial
applications. In addition, its core architects have launched a company called
Thingsquare[6] based on Contiki which aims to be Heroku for low-powered
wireless devices.

[1] IPv6 over Low power Wireless Personal Area Networks

[2]
[http://redwire.myshopify.com/collections/frontpage/products/...](http://redwire.myshopify.com/collections/frontpage/products/io-
embedded-router-contiki-based)

[3] [http://www.ti.com/product/cc2538](http://www.ti.com/product/cc2538)

[4]
[http://www.atmel.com/tools/atsamr21-xpro.aspx?tab=devices](http://www.atmel.com/tools/atsamr21-xpro.aspx?tab=devices)

[5] [http://contiki-os.org/](http://contiki-os.org/)

[6] [http://thingsquare.com/](http://thingsquare.com/)

[7] If you want some CC2538-based open hardware:
[http://www.openmote.com/](http://www.openmote.com/)

~~~
madvoid
Excellent summary, thank you very much! Do you happen to know much about
DASH7[1] that you can explain as well?

[1] [http://en.wikipedia.org/wiki/DASH7](http://en.wikipedia.org/wiki/DASH7)

~~~
bradfa
DASH7, the alliance, is a failed enterprise, imho. Their spec and OpenTag
firmware both look great from a high level but once you attempt to use them
you will find huge holes in the implementation of each.

ISO 18000-7, although power hungry compared to most every proprietary wireless
protocol, is a well deployed and understood spec with many users. There is an
upcoming version of the spec with some new things, get involved in the working
group or get a draft copy to find out the details.

If you're looking for 433 MHz band RF, take a look at IEEE 802.15.4 and the
"f" and "e" amendments. These will allow you to do 6LoWPAN, if you want, or to
simply use the PHY and MAC layer from a international specification. Just be
aware of the "fun" you'll have in the 433 MHz band in different parts of the
world.

------
Aaronneyer
Interesting article. Any particular reason for resurfacing it now?

~~~
lam
Maybe it's a good time to update some of those figures. Eg, NFC range now goes
up to 10cm-12cm or longer. Also, it would be nice to include power consumption
from the ucontrollers that are used with those wireless transmitters to be
more representative.

