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mohitkhanna3v_infinate
06-19-2010, 12:40 PM
I have a main hub, and several other hand held devices. These several hand held devices need to communicate with the main hub bidirectionally at all times simultaneously. Can you please suggest me an appropriate Transceiver Module for the same. I'll be using Atmega8 or Atmega16 as MCU. Till now I developed my prototype application on standard 434kHz RF Transmitter/Receiver pair, and Ive shown that my application is successful in a single user scenario. Now, I need to develop it for multiuser scenario.

This application is for social benefit (something for the disable people), so I really need to keep the cost to the minimum.
Is it possible that with some modifications, I continue to use the standard 434kHz modules because these are quite cost effective? I'm bit afraid about the interference part though. Is it possible to avoid the interference or should I move to a separate transceiver all together?

On net I did find several Transceiver pairs but very less of them speak about the multi user scenario as I require.

Thanks a lot in advance for your help.

vikas
06-19-2010, 03:03 PM
You need to use transceivers which are addressable , these will come with SPI interface and not UART. So RFM12b is your cheapest bet ( Start at around 2 USD in bulk ) , I go them for about 4 USD /piece for sample quantities. These when bought in bulk with be cheaper and much much better than your UART interfaced 433 @ 4800 bps.
HopeRF has some other good ones too for longer ranges.

Also for communication please look into JEENode project , this is something on the lines what you are talking about. Anything else just ask :) .