Simple vehicle detection?

wkearney99

Senior Member
I'd like to have a way to passively detect the presence of our automobiles when they're parked in the driveway. Something that didn't induce a dead car battery by running all the time. Ideally something with a little solar cell to keep itself charged. We don't have EZPass modules in the cars (as they started gouging way too much for 'just having one').

I don't need to know anything else other than the vehicle is present. I've got CAT5 and other wiring within a few meters of the driveway, but only at a single location (no posts or other 'gates' on both sides). I figure max distance would be around 10 meters.
 
Specific to our automobiles I utilize these little RFID devices in the headliners adjacent to the dome lights.  The draw is minimal. I utilize three RFID recievers which are serially connected to the mothership.
 
They have been there for years.  I had one quit about 3 years ago.  Not a big issue to replace.
 
The three receivers run with two applications creating multiple variables; then I utilize an if then statement for all three variables.  Works for me (many years now).
 
The garage RFID box is in the back of the garage.  There is one in the attic and one in the basement.  The boxes do start chatting before entering the driveway.
 
Different folks have done different things with these little tags.  Some put two in their automobiles.  Some build better antennas.  The Mw 12VDC is minimal.
 
I am thinking they were around $40 USD each.  The receiver has a 9 pin RS-232 connector.  Mine are powered from the RS-232.  There is a supplemental barrel power connector on the receivers.  I have never used it.
 
I have them configured to talk to the mothership via two plugins.
 
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Easiest would be a basic loop detector and loop in the driveway. Same as the safety loop used for gate arm operators and similar.
 
Cheap (sub $40 total in parts).
 
Downside is it'd be any vehicle, if you care if it's your car or not.
 
"Easiest" would not include busting up brand new concrete or trenching for the wire.
 
That and I am looking to identify our own vehicles, as that'd be useful for triggering 'expected driver' conditions and schedules.
 
But it's one suggestion to consider.  I'd certainly have considered it if this were a long driveway, not just a typical suburban setup.
 
I suppose a passive RFID tag would be the simplest place to start.  I'd have to look into how the detector would have to be situated.  I've got a point at the 1st-2nd floor joists where there's some CAT5E & 16/4 pulled (expecting to put motion sensors there).  That or a place where a mailbox post is going to get installed.  I don't have CAT5 to that point, but I do I have unswitched power.  So a wifi setup there could work.  The downside would be it's alongside the parking spots, so the distant vehicle would end up blocked by the closer one.  The upper location is sited right in-between the two spots, just 11' above them.
 
I'd scour the 'Bay for a Transcore reader and then work on the RFID end then.....they come up reasonably often, are robust and reasonably cheap.
 
I'd prefer to find something that would be relatively discrete looking on a residence.  
 
Some of the readers I've seen are geared more toward 'serious' outdoor installations; like for overpasses and utility poles.  
 
Yup; here also have a Cartel setup connected to the HAI OPII panel. 
 
Many years ago utilized the little wireless X10 Eagle Eyes which also worked in each of the vehicles. 
 
Also used (dealt with) similar to what Del mentioned above at a gas and oil facility (more of little city).
 
Nice write up.  I'd prefer to avoid having to tap the car's 12vdc, as to avoid draining the battery.  So either something passive, solar or long-lived battery would be ideal.  That and tapping only an ignition-powered line doesn't give you full monitoring.  Being able to 'ping' periodically is one way to detect if it's moved without the ignition started.  Because nobody would ever think to drift a car back and then down the street to start it... 
 
I've been using the aforementioned little RFID devices now for a few years.
 
The little devices mentioned are also sold with one CR2032 3VDC battery.  The battery lasts for a bit over a year.  Tested this over the years.
 
Some folks have made up little battery packs for these using AAA or AA batteries; just makes the footprint larger. 
 
The ones I have in the headliners have not drained the car battery to date on one automobile that is driven about once a week. 
 
I have also tested these on the rear deck of the automobile near the speakers in the spaces where there are openings (no metal) and just in the trunk of the vehicle.
 
Noticed that the company has one that self contained which you can "register" up to 12 devices and use the devices to trip relays on the receiver.
 
Recalling now many years ago (1980's) my sister/brother-in-law got their car stolen at some 3AM in the morning.  It was a company late model vehicle that was always in the driveway.  Neighbors did call in the morning stating something about a tow truck pulling up to the driveway and towing the car away.
 
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