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ZigBee and 802.15.4

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

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) protocol is carried by the rails with a 10kbps bridged bandwidth limitation.

ZigBee (see

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) 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.

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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

Reply to
sap
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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

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and especially for the links of McZub !

Regards,

Martin

Reply to
Martin Maurer

"Martin Maurer" a écrit dans le message de news:

429d42a3$0$50706$ snipped-for-privacy@authen.white.readfreenews.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

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but this isn't the way to use it for HO scale. What ZigDCC needs is more like this:

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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:

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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,

Reply to
sap

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

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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

Reply to
sap

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

Cheers, Jon

Reply to
jon

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

a écrit dans le message de news: snipped-for-privacy@g49g2000cwa.googlegroups.com...

Reply to
sap

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