distance between the RFID Module and the Basic Stamp.
Hello Everyone.
I'm working on RF Access Control, but i have a litle doubt, Which is the maximum distance between the RFID Module and the Basic Stamp.
RFID Module =========================== BasicStamp
·································· 50m
excuse if it is a very simple doubt.
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Best Regards from Chile
Goten
www.chilebot.cl
·
I'm working on RF Access Control, but i have a litle doubt, Which is the maximum distance between the RFID Module and the Basic Stamp.
RFID Module =========================== BasicStamp
·································· 50m
excuse if it is a very simple doubt.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Best Regards from Chile
Goten
www.chilebot.cl
·
Comments
·· There is no fixed number of inches or feet...It really depends on a lot of conditions.· But for anything over 6" you need to start taking EMI/RFI into account.· After a couple of feet you need to consider line driving.· In thta case you should probably switch to RS-232 or RS-485/422 to get the signals the distance they need to go.
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Chris Savage
Parallax Tech Support
csavage@parallax.com
It seems that i have·a big trouble... there's 50 meters from the rfid reader to the basic stamp... as you said i'll have to use RS232, but... it really works? or i should use some repeaters or something like that?
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Best Regards from Chile
Goten
www.chilebot.cl
·
http://forums.parallax.com/showthread.php?p=602070
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Chris Savage
Parallax Tech Support
csavage@parallax.com
You might have to go to something like 300 baud.
If you already have 50 meters of wire and RS-232 coming from the RFID, why not try it?
Full-duplex RS-232 can be duplicated with two twisted pairs and RS-422 transmiter and reciever pairs.
Half-duplex RS-232 [noparse][[/noparse]where you have to wait for the other device to stop transmission] can use the RS-485 drivers.
In the beginning, I thought the half-duplex was okay, but you have to include software to make devices wait.
So IMO, I think the full duplex is easily worth the extra pair of wires -- you can use PBasic's SERIAL IN and SERIAL OUT without any extra hassle. It is just like DEBUG on your computer [noparse][[/noparse]the keyboard doesn't have to wait for the screen and vise-versa].
RS-422 and RS-485 is just much nicer for distances. Dr. Allen has used then in a lot of hostile enviroments with very very precise environmental data colllection.
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"If you want more fiber, eat the package.· Not enough?· Eat the manual."········
Post Edited (Kramer) : 8/26/2006 12:00:38 PM GMT
i'm just posting to say Thanks.
As kramer said, and for general info, RS232 works really good at 35 mt!, and also the Rfid Module.
Thanks
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Best Regards from Chile
Goten
www.chilebot.cl
·