Re: 6LoWPAN or any alteady avaible alternative

[ant <blowback@xxxxxxxxx>]

On 28 June 2011 13:36, Mussard, Mike J <m.mussard@xxxxxxx>
wrote:

Hi Mike,

> I'm looking for a home automatic protocol that is most open to end
user hacking and so far my research has pointed me in the direction of
6LoWPAN which I'm thinking looks like the way I want to go.

Personally I think 6loWPAN is promising, and plan to muck around with
this myself.  Google are rumoured to be experimenting with 6lowpan at
868/915 Mhz, but details of that are sketchy.

> I've found JENIC from NXP, but that looks like Q4 2011 from their
website and also I can't quite work out how it differs from proper 6LoWPAN
so how good jenic-ip would be at talking to non Jenic-IP 6LoWPAN devices.

The bit of the spec that deals with fitting ipv6 packets into 802.15.4
frames is well defined; what's currently still under active
investigation is the routing within the mesh. There seem to be broadly
two camps at the moment, "route-over" (network-layer routing with
IP
addresses) and "mesh-under" (link-layer routing with MAC
addresses).
There is a nascent IETF standard, ROLL (routing over low-power and
lossy networks). Jennet, I seem to recall, uses mesh-under. As long as
you stick with the same scheme throughout, you should be fine.
Route-over currently offers better reliability and fewer transmissions
per packet, but mesh-under has lower total delay. I expect route-over
schemes will eventually win out, mainly because they're easier to
implement.

> Are any of the technologies more open than others, or is it worth me
waiting this one out until I can get my hands on 6LoWPAN devices?

Also up-and-coming are DASH-7 and Bluetooth-LE. Both are likely to
have sufficient volume for cheap silicon, although BTLE is likely to
be harder for hobbyists to get in to. There's already plenty of choice
in the 6lowpan arena; all the major players have mcu+rf chips and
modules for 2.4 ghz; I found one the other day that had a 433/868MHz
6lowpan module, which would over range advantages and is a less
crowded band, but I can't find it for the life of me now :( If I
stumble upon it again I'll mail you a link.

My own plan was to choose modules that can run contiki
(http://www.sics.se/contiki/) - it's
nice and fast, needs few
resources, and is open; more importantly they already have a 6lowpan
stack (with ROLL routing). i'll use 433 mhz if I can find 'em,
otherwise the atmel module probably looks favourite (at least until
the jennic modules are more readily available).


> For a bit more background the kind of devices I'm interested are both
sensor type boards and also 12 volt control type boards e.g. for LED strip
that already requires a 12 volt DC transformer.

Awesome! Let's interoperate! ;)

cheers

ant


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