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ceasar
11-18-2006, 04:20 AM
I need a RF transceiver that has a range of less that 50feet and takes serial input/output

Newzed
11-18-2006, 04:29 AM
Try the XBEE at:

·http://store.kagi.com/cgi-bin/store.cgi?storeID=J1A_LIVE&&

Sid



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Sid Weaver
Don't have VGA?

Newzed@aol.com (mailto:Module?Newzed@aol.com)
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ceasar
11-18-2006, 04:41 AM
I looked into the XBEE and its range is to far for my application. Any others?

Newzed
11-18-2006, 04:44 AM
The XBEE will work from 1 inch to about 100 feet.· It will work just fine in your application.

Sid

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Sid Weaver
Don't have VGA?

Newzed@aol.com (mailto:Module?Newzed@aol.com)
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ceasar
11-18-2006, 04:50 AM
How do you limit the range on it, with the output power? If so, I thought the minimum range is 300 feet?

Newzed
11-18-2006, 04:56 AM
You do not have to "limit" the range of a transceiver.· If it says the range is 300 feet, that means it will work anywhere from 0 inches up to 300 feet.

Sid

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Sid Weaver
Don't have VGA?

Newzed@aol.com (mailto:Module?Newzed@aol.com)
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ceasar
11-18-2006, 04:58 AM
For my application I need the range to be less than 50 feet, so I need to limit the range.

Franklin
11-18-2006, 05:52 AM
Why do you need the range to be less that 50 feet? Perhaps if we understood that we could be of more help. How about a 50 foot wire and NO radio?

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- Stephen

ceasar
11-18-2006, 06:08 AM
This is a system that transmits and receives RF signals comprising of a master unit and a remote unit. For senior project, the Object Locator is to be implemented on a carrying case and cell phone respectively, wherein a separation distance between the master unit and remote unit is continuously monitored. An alarm is activated on the master unit when no signal is received from the remote unit for at least a time longer than a preset interval. So in order for this to be practical I need my signal to only tavel a short distance. 300 feet is to far. By the time my alarm rings after 300 feet of signal travel the phone will be gone.

Newzed
11-18-2006, 06:58 AM
Ceasar, what you are asking for is tacitly impossible.· In the first place, RF does not abruptly drop off at a certain range.· It just starts to attenuate.· Suppose you had a tranceiver that had a range of approximately 50 feet under a given set of conditions.· If you change the respsective elevation between two transceivers, if you change the orientation of the antenna, if you walk near a metallic object, or if you interpose something between the transceivers, the range will be shortened.·
I know of no communication medium - sonar, IR or what have you - that will do what you want.·

Sid

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Sid Weaver
Don't have VGA?

Newzed@aol.com (mailto:Module?Newzed@aol.com)
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PAR
11-18-2006, 08:10 AM
ceasar said...
This is a system that transmits and receives RF signals comprising of a master unit and a remote unit. For senior project, the Object Locator is to be implemented on a carrying case and cell phone respectively, wherein a separation distance between the master unit and remote unit is continuously monitored. An alarm is activated on the master unit when no signal is received from the remote unit for at least a time longer than a preset interval. So in order for this to be practical I need my signal to only tavel a short distance. 300 feet is to far. By the time my alarm rings after 300 feet of signal travel the phone will be gone.

Perhaps you need to redefine your phone's·world? What does it mean for your phone to be "gone"? Stolen? Forgotten and left behind? Is the carrying case (locator) "gone" ever also (i.e., with the phone)?

Which direction has the phone "gone"? Gone·ten feet somewhere into a crowd is more gone than going 100 feet on a street with only one other person out there.

I suppose I'd want to know where my cell phone is when it is no longer on my person and/or in my sight, which would lead to other possible (more reliable?) solutions for keeping tabs on it.

But, perhaps you have some specific, well-controlled circumstances of "gone" for which RF signals might be appropriate?

PAR