dumbest question ever

[donkey]

tranciever question

hey guys and gals need to know something. but feel stupid asking
http://www.ebay.com.au/itm/300661932937?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649
is that item worth the money?
I have a project that requires a reciever to pick up an unlimited number of transmiisions from multiple sources.
the idea is the transmitters go around a property and send data continuously, the reciever will recieve this data from all the different sources. when an "event" happens the transmitter switches to another code and the reciever will show which one it is that is out of whack.
there are 2 reasons i want this setup is a)conitnuous transmissions helps locate a fault quickly
and b) continuous transmissions help identify tampering.
please let me know any thoughts or any other way to do this

 

[Harald Kapp]

The description says the module has 125 channels, that's not quite "unlimited" as you require. So theoretically you can use up to 125 transmitters simultaneously - provided that the frequency spectrum is not used otherwise and that neighbouring channels do not interfere with each other.

Equiping each mobile unit is no big deal. The challenge is the receiving end.
You could use one receiver for each transmitter - ridiculous.
You could use one receiver and have a controller make it scan all channels sequentially.

If you want to go over 125 mobile units, another scheme will be required. How about this one:
Have all transmitters tuned to the same channel. The "base station" is the master, all mobile units are slaves. Each mobile unit has a unique address (e.g. a 32 bit number which gives you an "unlimited" number of unique mobile units). All mobile units are normally in receive mode only. The base station issues a request by sending the address of a mobile unit and then switching to receive mode. The addressed unit switches to transmit mode and sends an acknowledge signal, then goes back to listening in slave mode. Thus all mobile units can be checked by polling them.

What I'm unable to judge is whether this particular type of transceiver is capable of turning off the transmiter while listening. Otherwise the trnasmitters of different mobile units would interfere with each other. At 2.33$ that is something that you can test at a comparatively small expense.

Harald

 

[(*steve*)]

They actually look pretty cool. If you get some, tell us how they go.

This may be the datasheet.

 

[CocaCola]

My biggest concern would be that the 2.4GHz band as it's already over used, these small devices might simply be overwhelmed by existing traffic and noise and fail to perform over anything but very short distances...