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Topic: Available shields and shield ideas (Read 7 times) previous topic - next topic

Eric T

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I had seen that and I thought that I had added it to the list already but apparently not... It looks good.
I will be buying one of those, It would also be a good prank board!
Mowcius

I hadn't thought about using this for pranks?  ;)
If you do create a prank with this board I'd love to see it in action.

- Eric

novice

@Inopia
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Why don't you get an xbee shield if you want Zigbee?

I know I can.

As previously stated "I suggest that your cheap node implementation be at least Zigbee compatible so it is marketable."

I'm only suggesting this to help you.

Inopia

@novice, vixr: Zigbee compatibility comes on two levels. On one hand you have the radio that implements the physical and MAC layers, and a network layer that performs routing, among other things. On the other hand you have modules such as xbee that allow you to talk over zigbee from an MCU, usually via serial. These modules have their own MCU that implements all the zigbee stuff in software.

If you save money by eliminating that MCU and doing everything on the AVR you're going to have to run a network stack on the AVR along with your application, so the second case of zigbee compatibility obviously does not apply. The first case is a matter of implementing a standard. The biggest problem is that if you run both the network layer and applications on one chip you're going to need something that enables multiple threads of control (and no, interrupts aren't going to cut it). Several such systems have been proposed using 'real' multitasking/threading (Mantis, freertos), protothreads (Contiki), and event-based programming (TinyOS). Personally I prefer Contiki although my goal is to just do everything in Java and use green threads.

So 'Zigbee compatibility' requires either a second MCU (which is what xbee modules have) or a more advanced 'os' or runtime or library or whatever that lets you do multithreading in a sane way. If you want complex network features you're going to need something other than the Arduino language. For robotics/wsn I'd suggest you take a look at Contiki (http://www.sics.se/contiki/about-contiki.html), which has a wireless stack called RIME that's already running on the AVR Raven boards which use about the same setup as what we've been talking about (avr+atmel 2.4ghz rf), so should be trivial to port. It's IPV6 baby :3

For just simple point-to-point communication in the absence of another 2.4ghz network on the same channel you can just send raw packets over the radio. Control your Philips ambilight and such :) It's perfectly fine for applications such as controlling your coffeemaker wirelessly. You only need Zigbee or something like that for large scale, multi-hop networks, or for integration with existing Zigbee stuff.

As for open sourcing I already open source my efforts under the LGPL license, my JVM can be found at http://darjeeling.sourceforge.net/.

Inopia

So I've done a little digging and found a software library for the AT86RF2xx chips from Atmel:

http://www.nongnu.org/uracoli/links.html#RCB230

It seems to do all sorts of cool stuff from low-level to high-level, such as mesh networking or simple wireless uart.

novice

Inopia,
does that communications library put you in a position to make hardware decisions?. It appears that vxir is 'keen as mustard' to help you on the h/w side.

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