Hi folks,

I am now a little bit confused. Is ZigBee 802.15.4 or is ZigBee on top of
802.15.4? I'll have to read that 802.15.4 spec throught.

What are the news about open source and embedded applications taking
benefits from those standards?

Did anyone of you evaluate Chipcon hardware, the CC2420 chip? The next 2520
looks promising as that one will be even smaller in size and will require
only 2 layers PCB (according to 2500 chip reference design).

I would have a huge project to start with (from scratch and specifications).
I hope we already can play and enjoy the lower layers provided by chips like
CC2420 or is this currently closed?


Today I feeded a project into sourceforge. I hope it won't be rejected due
to licensing concerns...

Part of its abstract is following:

Since the 80s DCC (Digital Command Control for model railroad, see
http://www.dcc.info/ ) protocol is carried by the rails with a 10kbps
bridged bandwidth limitation.

ZigBee (see http://www.ZigBee.org/ ) is one of the latest industrial
wireless standard (UMTS - WiFi - BlueTooth - ZigBee) for small embeded
devices allowing up to 250kbps bridged baudrate in ISM 2.4GHz public band.
ZigBee has a small footprint in embeded systems (4k to 32k) and is really
affordable (less than $10 per RF end system with the miniature antenna)

ZigDCC project will allow the use of ZigBee to carry DCC signals between
handhelds and DCC decoders. Many boxes from the 80s will be thrown out the
way by ZigDCC, even the more silliest. This will improve performances and
expand perspectives of model railroad gaming. ZigDCC will also drastically
improve hardware interoperability. By many ways ZigDCC will ease DCC systems
usage and lower aquisition costs of next generation DCC systems. Prototypes
can be made available for mid 2006.



www.ZigDCC.org because the DCC data should Zig throught RF links and nodes
(shortest path indeed) untill it reaches its destination node... but as most
destinations are moving locomotives, destination may have wanished from
there and is reappeared elsewhere on the layout :-)

Must be open source / open hardware / open embedded hardware using the
latest available technologies (must be performant and fit in small scales,
initial target being most common HO 1/87 scale).

Must also integrate and cowork with existing DCC systems.


Any interests to feed in contributions?
PICs, AVRs, ARMs knowledges and experiences welcome, newbies also :-)


Best regards

Hello,

as far as i have understand, 802.15.4 gives the lower layer and Zigbee sits
on top. At the moment the Zigbee spec is not yet public available.

I have a few of them running (at least basic transmission, not yet Zigbee
nor 802.15.4 compatible), have a look at my page http://www.clibb.de and
especially for the links of McZub !

Regards,

Martin

"Martin Maurer" <Martin.Maurer@clibb.de> a écrit dans le message de news:
429d42a3$0$50706$892e7fe2@authen.white.readfreenew s.net...
So this probably means ZigBee RF ends will be soon sold for $99 a piece for
basic RS232 - like most do for BlueTooth modules...
Which is heavy for 4k RFD foot print.

brings me to
http://blogger.xs4all.nl//images/blo.../r_rf_comp.jpg


but this isn't the way to use it for HO scale. What ZigDCC needs is more
like this:
http://www.eazix.com/products/zigbee/ezzbm01a.jpg

this module is just lacking a small 1cm² area for a SMT PCB antenna and some
more components at the rear side or in extension, mainly for motor control.

Those are HO scale locomotive decoders only RF heads are missing:
http://www.merg.org.uk/resources/Dec11.jpg


Mouser.com sells the CC2420 chip alone and a 2.4GHz antenna for approx $8
the bundle. We are far from what you paid for ref designs.

Regards,

looks like a mczub/IEEE802_15_4 stack for FreeRTOS, this is just fine and
suitable for PICs or AVRs.

ZigDCC can be close over MAC layer, bridged and broadcasted in a first
stage.


you want to use sensors? if you go and check on http://tinyos.net/ you will
notice they got closed source object files which do support ZigBee.

what is TinyOS:

TinyOS is an open-source operating system designed for wireless embedded
sensor networks. It features a component-based architecture which enables
rapid innovation and implementation while minimizing code size as required
by the severe memory constraints inherent in sensor networks.

Regards

ZigBee is the NWK layer (and up), 802.15.4 is MAC, PHY and RF.

Cheers,
Jon

yep, this is what I finally understood.
and expensive ZigBee stack for upper layers seems not necessary for my
app...

<jon@beniston.com> a écrit dans le message de news:
1117643923.514261.203440@g49g2000cwa.googlegroups. com...