Vehicle detection

Here I have been longer with my parrot than my wife (35 years?). 
 
The parrot has some key words that triggers an automated response (literally) from my wife anytime of the day their domains cross. 
 
I then walk over to see what the commotion is about and the parrot appears to be docile and starts to make a  "cooing" sound and saids that she is a good bird telling me that she loves me. 
 
Parrot is getting old now, falls asleep on her perch; then wakes herself up falling off her perch in her sleep. 
 
She did also some 20 years ago attack our dog nipping the dog in the snout.  Blood everywhere; dog never did bark at her again after that (the illicited automated response).  
 
These are all automated responses which started a few years back.
 
The more I read your posts the more I am intrigued! Forget dos equis! The most interesting automator alive: I don't always automate, but when I do, I prefer my parrot!
 
It occurs to me that each of my vehicles is already equipped with an active RFID tag - E-ZPass, which is the toll collection system in use in my area.  I've done some searching and while I see these tags are being used for other purposes like parking and have found some rudimentary info on the protocol they use, I can't find anything useful that would help me build a reader for them.  If there was just a way to read the unique identifier from these tags, it would be a great way to see which vehicles are present.
 
Look under technology details:
 
http://en.wikipedia.org/wiki/E-ZPass
 
In short, I think you will have difficulty reading them without the reader from the supplier. Most of the time these things are proprietary and you have to be authorized from the supplier to get parts. Especially when money is involved....
 
Awesome idea, btw...
 
They apparently have been hacked. How dedicated are you?
 
I found a bit more information about the IAG protocol these tags use here:
 
http://www.mail-archive.com/[email protected]/msg02082.html
 
It sounds like it should be possible interrogate the tag and get a response using non-proprietary equipment, but it's not clear whether the response would be encrypted or not.  Actually, if at least something in the response is unique to the tag and repeatable, it should serve the purpose of identifying the vehicle for HA purposes.
 
I'm very interested in pursuing this, but my technical knowledge and abilities are not quite up to this challenge.
 
Some of the older units weren't even using encryption (more here), so in theory, it would be relatively easy to monitor these devices.  I would guess these devices have been updated by now.  It's definitely an interesting approach.
 
Another approach I would consider (and might be easier) is monitoring the TPMS sensors which almost all new cars have.  With a great reader, you should be able to capture this data (and maybe even alert you to tire problems).
 
I like the TPMS thing. 
 
I had one of those legacy transceivers.  It was really nice that it beeped and had a nice LCD display on it.  Keep track of totals and every toll booth. 
 
I did get emails to update my old one for months and I ignored them because it appeared that mine was still working just fine.
 
A couple of years ago I got an email stating that my device had been reported stolen and that I was getting fined for passing a few tollbooths without payment. 
 
That said I was "asked"  to get a new one with no LCD and no beeper on it such that I wouldn't be fined anymore.
 
Here is another article on same stuff that Dan posted.
 
http://www.technologyreview.com/news/410743/road-tolls-hacked/
 
I did find a newer higher end RFID ID device on Ebay that doesn't look too shabby.
 
http://www.ebay.com/itm/Long-range-UHF-Active-RFID-Tag-and-RS-232-Reader-922-928-MHz-RTLS-Dual-CR-2032-/290874064908?pt=LH_DefaultDomain_0&hash=item43b972000c
 
Reading the TPMS sensor IDs sounds like another promising solution, but what would the practical range be?  I expect it is farily short so the system does not get confused by other nearby vehicles.  One of the cars I want to monitor is parked outside about 30 ft. away.  That's one of the reasons I was thinking of the E-ZPass approach.
 
I rotate between winter/summer wheels, and only the summer wheels have the sensors.  I put them 3' away from where the car parks, and the car picks them up just fine (or it would give me a flat tire error after ~50miles/60 minutes of driving).  I would think that with a good antenna, the reader should get more range.
 
I would love to experiment with the TPMS monitoring for vehicle ID.  Any suggestions on an (inexpensive) external TPMS reader with a serial or USB interface?
 
scottmi1 said:
It occurs to me that each of my vehicles is already equipped with an active RFID tag - E-ZPass, which is the toll collection system in use in my area.  I've done some searching and while I see these tags are being used for other purposes like parking and have found some rudimentary info on the protocol they use, I can't find anything useful that would help me build a reader for them.  If there was just a way to read the unique identifier from these tags, it would be a great way to see which vehicles are present.
You don' t want to know how expensive the units are. We installed all of the units for our state's airport facilities as well as a bunch of other sites. The largest problem is getting a unit to provide enough sensitivity for read range, the protocol and credentials aren't the issue.
 
I have TPMS built into the cars and I think the transmitters are the valve stems. 
 
Its a simple non text dummy LED which just shows a picture of a tire.  It does always go off when there are some major changes in the ambient temperature.  Checking the tire pressures after the light going on and I never do see much of a change in the tire pressures.
 
Years ago (think it might be posted here) someone wrote up a per automobile use of those X-10 Eagle eye motion sensors.  I think I used that for a bit in the early 2000's.  It worked OK.  You could also do garage analog type floor mat switches.
 
Here is what I see with my "cheaper RFID" stuff.  3 receivers and 1 tag in each vehicle.  Basically the application does state which receiver is seeing the tag first.  I take all three variable and assign the ON/OFF for a period of about 1 minute each with no change.  I have one receiver in the attic with an inverted scanner antenna, one in the middle of the house buried in a wall and one in the garage buried somewhere.  The resultant single variable is the result of three if then statements and it does work OK for me.  The newer generation offers some signal strength stuff in addition to the rest of the data. 
 
Tags are easy to see/check using a terminal serial connection. 
 
 
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The TPMS sensor mounts on the back of your valve stem, inside the tire.  It's about the size of a pack of gum, maybe a little larger. 
 
Personally if you installed a 3rd party TPMS setup then it would be easier to take apart the system to reverse engineer it modifying to your liking.  
 
I think that the car manufacturers are using different means of TPMS and haven't really decided on which means is better. 
 
Mine sucks (BMW is antiquated?).  That said though I can almost totally remote control my car today with the car PC as the bus communications has been documented. I nevers sniffed the bus to look if the TPMS system was on the same bus.  It probably is.
 
Because of the commercial use of RFID the prices of the equipment is high. 
 
But really the technology is simple and you can purchase it cheap if you look. 
 
You can also purchase used commercial RFID stuff that is not worth anything to owner for a fraction of the original cost.
 
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