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**Rupp** · May 21, 2002, 08:10 AM

There was a thread for a low tech version of this using Hawkeyes as the transponder. Its an interesting idea.

http://ubb.homeseer.com/6/ubb.x?a=tp...4&m=8022912215

-Rupp

**Barry Gordon** · May 24, 2002, 10:26 AM

I also found a firm that makes RF transponder systems for parking garages. The RF tag is pasted on the windshield (about 1.5"x2"). The RF reader is mounted lets say above the garage door aimed down. In theory when your car gets close the tag starts sending its ID using the RF field of the reader for power (Straight RFID technology). The unit has about an 11 foot oval shaped radiation lobe so it should work fairly well. It has RS232 outputs so it would be easy to integrate. tags are reasonable (about $10); the reader is not (about $1500). I will push a button for that cost.

**Stevech** · May 24, 2002, 05:20 PM

I've worked in this field called "RF ID". It's not likely you'll find a tag reader for hobby-type prices.

I can think of other on-car transmitter approaches:

- a bare bones car alarm key fob receiver and a key fob. Maybe $50 or less. Receiver goes in your house powered by a wall transformer. One of its outputs, like door lock, it wired to an X10 universal module. The key fob goes in the car, powered by 3v derived from the car's 12 volts. A 50 cent 555 chip oscillator can pulse the fob to transmit every few seconds. Key fob mounts under dash or in a cool, non-metallic dry place in the front bumper area.

- Old TV/stereo IR remote pulsed by a 555 chip - installed on the car. A $25 "IRman" IR receiver connected to your PC via a serial port. PC gets a data message when the IR is in range and remote on the car is able to illuminate the IRman according to some cosmetically pleasing scheme.

What I'd really like is a 30 gauge wire epoxied to the garage floor (low profile, no tripping hazard). Car's wheel rolls over it. Magnetic flux change sensed by a simple circuit (for which I have a notional idea). Like the sensors at traffic lights. Maybe two of these sensors - for unambiguous coming/going. ---- It would also light a LED to serve as a parking stop-here aid.

**huggy591** · May 24, 2002, 05:47 PM

You might even be able to use surplus bar code readers and stick a bar code tag on your car. Bar codes can be read at fairly long distances depending on the reader. I wonder if you could do it with the freebie Cuecat from Radio Shack? Wouldn't that be a neat hack?

[img]/infopop/emoticons/icon_wink.gif[/img]

- huggy

**Stevech** · May 24, 2002, 10:13 PM

bar code - nah. cheap readers have a range of about 4 inches or less. CueCat (I have one) is less than that.

**Barry Gordon** · May 26, 2002, 06:57 AM

Stevech,

Your solution intrigues me. I have to think about the timing so that it makes sense,

I should be able to design a finite state automata to define all of the possible conditions and the transitions between them. The key state variables will be things like: Car pulsing, Car not pulsing; Garge door open; Garage door closed. There will then be some derived states that are based upon timings. It should not be that hard. I have an advantage. Homeseer already knows about the garage door states. And home seer has contact closure input plus digital I/O via a lynxport.

I will have to play with this some more. Thanks for the thought

**pmonahan** · February 4, 2005, 05:25 AM

RFID with Active Tags Nearing HS Beta Test

Have you seen our Post at:

http://board.homeseer.com/showthread...highlight=RFID

This is proven technology that we have adapated for HA use. It is NOT 2.4 Ghz as in other examples, rather the tags are ACTIVE, we are getting prepared for beta test of the plugin.

Round 2 of the beta test will take advantage of a built-in motion sensor in a new model tag. In this regard, we will not only be able to tell you that the tag is detected or leaves the field of the reader, but if it is Moving.

Thanks

Peter

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