PDA

View Full Version : Transceiver Protocol



Left_Jab
07-17-2011, 12:19 AM
Hi,

I would like to know which protocols are being used nowadays with the transceiver HopeRF RFM12 (not 12b). I intend to use it in a wireless mesh network.

Also, please let me know whether SNAP (Scalable Node Address Protocol) is still a popular choice or whether it has become obsolete now.

Thanks!

Left_Jab
07-17-2011, 10:07 PM
In my question (above), I did not mention the specifications of the device I am using: it runs on 433 MHz and uses FSK. So what I'd like to know is whether a protocol exists for any device having these particular specifications.

Mike Green
07-18-2011, 03:09 PM
As far as I know Zigbee (http://en.wikipedia.org/wiki/ZigBee) is the most commonly used mesh networking protocol for embedded systems. You are unlikely to be able to run any kind of complex protocol on a microcontroller like a Stamp because of limited memory and speed. A Propeller would be much more capable, but most people these days buy an off the shelf system like the ones from Digi (see intro here (http://www.parallax.com/Store/Accessories/CommunicationRF/tabid/161/CategoryID/36/List/0/SortField/0/Level/a/ProductID/718/Default.aspx)).

Left_Jab
07-18-2011, 08:54 PM
Hi Mike,

Thanks for the help. I also considered using Zigbee, however, it would be too costly(compared with RFM12). That is the reason why I want to use a device that does not have a built in protocol.

" You are unlikely to be able to run any kind of complex protocol on a microcontroller like a Stamp because of limited memory and speed."
This, I think, is quite important for me to consider. However, I dont have much idea about which protocol would be considered "too complex". But do you think I could implement a protocol like IEEE 802.15.4c on, say, 8051?

Also, I was reading about Dash7. There's not much information about it available - for that one has to become a member of Dash7.org
But I think they do have a protocol for 433MHz FSK devices. Do you have any idea about Dash7? And do you think it would be worthwhile for me to implement it in my system?

Mike Green
07-19-2011, 02:00 AM
Never heard of Dash7, sorry. Remember that this is a Parallax support forum, mostly for devices using Parallax processors. There's general support for using Parallax products with other devices, but not the level of detail that you probably want. I suspect that you could implement IEEE 802.15.4c on something like a fast 8051 with lots of memory. There's no way you could use a Stamp for this and a Propeller would require some external memory, some kind of SRAM. 32K shared between data (buffers) and code is not enough for this sort of thing. There are several board designs for this that people have used (and sell).