Extending a PIR module to 35-70 feet away with phone cable. Can this be done?

RobertFowler

I have 5 PIR modules (Motion sensors).

I'm trying to build an elaborate home alarm system with motion sensors both inside and out. I have seen the 14" Servo motor/LCD cable that looks as if it would fit the PIR·module. I would like to know if I adapted it to telephone cable, would it work over a 30-70' run of cable? Even if I power the sensor from the central base, not at the sensor? I guess I'm woried about the resistance and potential capacitance of the cable. I'm no electronic engineer and don't know if these effects will come into play or not.

LoopyByteloose

If you have a remote PIR with its own BasicStamp and power source, the Stamp could handle sending data 70 feet via RS-232 or RS-422/485 drivers. Just the sensor alone is likely to fail as it was intended to sending data a few inches on a circuit board.

The BasicStamp would act as a data collector and repeater. You might even use a BS1, if you want both the lowest cost and low power consumption. For RS-232 you should use a MAX232 or an ultra low power version. Maxim also has ultra low power RS-422/485 tranceivers. Anything not ultra low power will quickly consume batteries.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"Everything in the world is purchased by labour; and our passions are the only causes of labor." -- David·Hume (1711-76)········

···················· Tropically,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan

tommy

...my goodness ! - a remote basic stamp isn't cost effective at all.· an SX-chip could bring the price of a remote PIR below $10.00 - two wires on a quad telephone wire would carry power; the other two could carry signals...· but what you're making is a common motion-sensor, available for $10 to $15 at any alarm store...· which comes in a case, ready to slap on the wall...

... I'm not recommending this store - I just pulled it out of a list -·· http://www.homesecuritystore.com/ezStore123/DTProductList.asp?p=2_1_1_1_0_0_14

· ... but a cheap detector sells for $17.50.· wireless models are available, too.

... and, YES !··150 feet of common telephone wire will·allow commercial PIR sensors to operate normally.· Typically, they operate on twelve volts sent over two conductors.···· (and like Kramer, I think it's a stretch to expect it to work with Parallax's modules...)

·tommy


Post Edited (tommy) : 10/1/2007 3:19:38 PM GMT

RobertFowler

Thanks Guys.

@Tommy, That link is exactly what I neded!!· I would·prefer to buy·a self install security kit but I went to several retail outlets and couldnt find any. They used to be popular but it seems like none of the big home centers carry them.· Don't know why I didn't find them online when I looked!!!· ·That link has everything I need.··· I was only considering building it from the Basic stamp because I already had 5 parallax·PIR modules.··

Thanks Again!!!