zigbee net

Kind of a general question (and I am muddling my way through the Xbee docs) --

Is it possible to hop a message through a Zigbee network back to a "host" or a "master"? I didn't see this addressed in all the discussion of Zigbee distance limits. It would seem that as long as a couple Zigbees are always close to each other they could pass data on through. It also looks like the Xbee modules have various modes that support something like this (maybe easing how much networking layer needs to be on the Picaxe).

If the Xbee supports this as part of the package it would seem to offer a huge advantage over the 443MHz modules for multiple sensor networks. Any comments are appreciated.

This is completely realistic. XBee modules can uniquely address each other and so you could even dedicate a unit to be a 'message relay' station.

But using WiFi home made aerials can greatly improve range and may make this unnecessary to start with. Try a google search for ideas.

ZigBee allows 'mesh networks' so, as long as there's a path, the message can hop towards its destination automatically. I'm not sure if the XBee firmware supports that configuration, and I think it was a future plan when I last looked ( not under Rev-Ed's control ).

http://www.maxstream.net/products/xbee/xbee-oem-rf-module-zigbee.php

http://www.maxstream.net/support/knowledgebase/article.php?id=168

By using back-to-back Xbee's a forwarding mecahnism could be built, and by embedding ID within the user packets sent, a single XBee can broadcast to all others and it shold be possible that way.

The alternative of re-configuring an Xbee forwarder on-the-fly is possible, but isn't instantaneous and would take some work.

On the topic of WiFi antennas, check out the lastest issue of <i>Silicon Chip </i> for their DIY bargain WiFi antenna solutions - cheap, simple and effective. Better yet, check out Stan's article, also in <i>Silicon Chip </i> , on Wi-Fry antennas! A great read even if you don't decide to use that method...

<b><i>ylp88 </b> </i>

Edited by - ylp88 on 08/05/2006 16:30:42

Thanks for the response.

Also - found a good, basic article at -

http://www.techonline.com/community/tech_group/36561

There does seem to be new firmware available ...

<b>Download X-CTU </b>

You'll need a copy of X-CTU 4.9.8 for Windows 98/ME/2000/XP (10MB).

This allows direct interrogation of the XBee module, downloading of Firmware Upgrades, and allows the Firmware to be upgraded.

http://www.maxstream.net/support/setup_xctu_4.9.8.exe

Usual installation method, and you should end up with an X-CTU icon on your desktop.

<b>Getting Firmware Upgrades </b>

Run X-CTU ( Xbee not needed ), select the Modem Configuration tab, and click on Download New Versions button, top right.

This will download the latest firmware upgrades for all NetStream products. It should bring with it XB24 versions 1080 and 1081.

<b>Upgrading Firmware </b>

Connect an Xbee to the PC; an AXE210 board with MAX232 ( no PICAXE ) is the easiest way.

Run X-CTU. Select the COM port, set Baud Rate at 9600, click the Test/Query button. This should show the Xbee as working - &quot;Modem Type = XB24&quot;, &quot;modem Firmware Version = 106&quot; in my case.

Select the Modem Configuration tab, click the Read button. You should get a list of configuartion settings shown.

On mine, &quot;VR&quot; Firmware Version is 106, &quot;HV&quot; Hardware Version is 1705.

Click Write button just to make sure updating works. Check the messages at the bottom.

<i>The following is done entirely at your own risk, and read to the end of this post before doing it ... </i>

Change Version drop-down box ( top right ) to 1080 or 1081, tick the Always Update Firmware check box. Click Write again and this should upgrade the firmware.

<b>Bugger </b>

I get &quot;Getting modem type....OK / Programming modem...Lost communication with modem / Write Parameters...Failed&quot;.

Checking the No Baud Change box under PC Settings tab makes no difference.

A Read shows that the old firmware is still intact.

Anyone doing any better than that ? Anyone know why it isn't working ?

Edited by - hippy on 08/05/2006 17:52:13

hippy - Maxstream docs for Xbee show the use of the CTS (pin 12) and RTS (pin 16), but the AXE210 docs don't show this. Maybe that is what the Maxstream software is looking for. Ps - I can't test anything at this stage as all I am doing is a paper design -- soon will be ordering some AXE210's.

ZigBee of course uses the same 2.4GHz spectrum as WiFi &amp; Bluettoth, so exactly the same antenna can be used for range boosting/interference nulling. All our infamous -ahem- <b> Chinese parabolic cookware </b> <A href='http://www.usbwifi.orcon.net.nz ' Target=_Blank>External Web Link</a> approaches are viable, and can give LOS ranges of several km <A href='http:// www.picaxe.orcon.net.nz/zigscoop.jpg ' Target=_Blank>External Web Link</a>.

Given the likely XBee use however,I rolled up (mmm- bent up ?)a super simple design (~9dB gain via NetStumbler on a WiFi AP) to suit the Rev.Ed unit =&gt; www.usbwifi.orcon.net.nz/plaspara.jpg <A href='http://www.usbwifi.orcon.net.nz/plaspara.jpg ' Target=_Blank>External Web Link</a>

We managed a good 1km LOS between identical 1mW devices with these - the bare 1mW XBees gave just ~200m &amp; were extremely influenced by obstructions such as vegetation &amp; even ones body. Indoors, only ~20m in a timber building was typical for the bare Xbee units however- still not bad for 1mW !

Contacted MaxStream ( and got a very fast response ) and, as davefish2 suggested, there are a number of other handshaking connections which need to be made to permit firmware upgrades.

The AXE210 board only has a 3.5mm jack, so a 9-way D has has to be connected by flying leads, but there should be unused buffers in the MAX232 to handle it. I haven't traced the board out yet, but will let you know how that goes.

I imagine MaxStream ship XBee's with the latest firmware installed, so not everyone will need to upgrade firmware, and not everyone will want to; the older firmware is more than adequate for most uses.

There's an updated manual for the latest firmware on the MaxStream site ...

http://www.maxstream.net/products/xbee/product-manual_XBee_OEM_RF-Modules.pdf

Some very interesting stuff has been added since I last looked -

* Co-ordinators, which will pass packets around the network and handle node hoping, and a lot of configuration options to set this up.

* Named node identification, node name discovery, and mapping of names to addresses.

* Auto-scanning of network, Clear Channel Assessments, Energy Scans and error reporting all of which help in configuration and diagnosing problems.

* An 'API mode' which handles binary data transfers rather than the Hayes modem-style interface.

On the plus side, XBee/ZigBee capabilities are considerably improved. On the down-side, it's a lot more complex than it was before; if you thought the manual was impenetrable ...

However, it still looks like the XBee is almost plug-and-play when factory reset, with just the usual channel and addresses which need setting for PICAXE use.

I agree with Hippy, &amp; point out to ZigBee propects that the XBee/Picaxe combo is not yet for the faint hearted! Although exceptionally powerful, when compared with rustling up 433MHz wireless links, a ZigBee approach will be at least an order of magnitude more involved. For simplex (1 way) wireless comms &amp; control, 433MHz is still a champ. Picaxe ZigBee comes into it's own for duplex (2 way) work.

To my mind, the best XBee/Picaxe setup coverage is in the April &amp; May 2006 Australian &quot;Silicon Chip&quot; <A href='http://www.siliconchip.com.au/cms/A_106456/article.html ' Target=_Blank>External Web Link</a> monthly, thanks to Rev. Ed's Clive himself.

And another &quot;bugger&quot;; the AXE210 uses a MAX3232 which has only single in and out buffers, not a pair of each. So that's another project on hold ( I refuse to pay three or more times the cost of a chip for P&amp;P ).

Yippee - Un-buggered !

Decided to try the PICAXE 22K trick via 74HC00 ( at 3.3V ) to create the RS232 inversions ... and it worked; can upload 1080 and 1081 firmware.

<b>It worked for me, but doing this is entirely at your own risk. No guarantees. No refunds. Double-check you've got it right, resistance check the circuit is corrected before power-up, and you're advised to check/prove my description hasn't got errors in it. </b>

Built a strip-board circuit to hold the 74HC00 and it needs the MAX3232 in-circuit.

The 9-way D-wiring ...

Pin 1 - N/C
Pin 2 - To single centre pin of 3.5mm Jack
Pin 3 - To double pins of 3.5mm jack nearest centre of board
Pin 4 - Via 22K, to 74HC00 to XBee DI8
Pin 5 - 0V
Pin 6 - N/C
Pin 7 - Via 22K, to 74HC00 to XBee DIO6
Pin 8 - From 74HC00, from XBee DIO7
Pin 9 - N/C

Test normal operation via serial via 3.5mm, then through 9-way without 74HC00 fitted to check that the module can be communicated with.

I wouldn't recommend keeping the 74HC00 in place after use. It only takes a few seconds to upgrade the firmware. Run from a reliable PSU because you probably don't want power loss while altering the flash.