433.92 transmitter/receiver

neolit2k

Good evening to all, I am new to this topic and thus I am in great need of help. I am working on a system that will send ascii codes to a main frame, such as a computer. The communication radius is 300 feet long, thus one transmitter/receiver module will not work. I need a network of transmitters/receivers to relay the signal from point a to point b.The big picture of such project being, that if someone on a school campus gets hurt they can transmitt a wireless help signal and within minutes they will get assistance. Any help is greatly appreciated.

petel6

Maybe I am missing it, but why not get the transceiver module, when you receive a help signal just turn around and immediately transmit it on to another module. Relay it on as many times as you need to. It basically only requires a serout at the transmitter and serin at the receiver, you can code the signal however you want to indicate the need for help.
So at the extreme radius of the area, where·you have the help butttons, if I had·a Stamp with a transmitter, hit·the button, it just does a serout to the transmitter of a one byte signal encoded to help indicate the situation. Say I send out an "55" byte. If I have another Stamp based system centralized that receives it, it just turns around and resends it via the transceiver it has, to a receiver at the security station. Or, since maybe the security station, might see the original·"55" byte, I can instead send out a·"77" (upon receipt of the "55") to the security station, if the security station saw the "55", it has·already been notified, otherwise it will get the relayed "77" which will tell it of the situation instead.
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Martin Hebel

I am currently working with XBee units from Maxstream. These are 2.4GHz, point-to-point transceivers which use the 802.15.4 protocol. Devices are addressable, with acknolwedgements. We used then this semester in class for a few weeks and they are really great. Within the next week or two I'll be designing BoE app-mod style connectors for them. Depending on the module, ranges are 300 feet to nearly one mile (line of sight).

http://www.maxstream.net

-Martin

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Martin Hebel
Southern Illinois University Carbondale - Electronic Systems Technologies

Personal Links with plenty of BASIC Stamp info
StampPlot - Graphical Data Acquisition and Control