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RFID (revisited)

I did a group search for RFID tags, and found nothing recent, or relevant. Maybe the state of the art (cost) has changed, and somebody knows something. I would like to place a tag on a telephone pole every mile that could be read as the train goes by to confirm location. The tag could be powered by battery/solar in order have enough poop to make the ~30 foot distance. Any suggestions?

As I think about it, maybe I could just mount a tiny transmitter that chirps out a quick data burst every so many seconds, and use a little receiver on the train to interpret the data. Since xmtrs are a mile apart, there won't be interference, and the short burst might make the battery run it OK. (the train goes no faster than 25 mph).

This will probably evolve into too many variables and not enough equations ;=)

Regards, Don

Reply to
blueflash
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SAVI Technologies makes exactly what you want...

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...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC\'s and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.
Reply to
Jim Thompson

Unfortunately, although RFID is a very active area right now, a lot of it is done under non-disclosure/private contracts/etc. so you won't find as much about it on the web as you might expect.

Ummm... can't you just put a GPS receiver on the train and it'll always know where it is? Or where you looking to somehow link your sensors together so that, shortly after the train passes by a given pole, that fact is communicated to a control center/database/whatever some distance away?

Usually the variable that becomes difficult to solve for is the one representing money. :-) What kind of budget were you thinking?

---Joel Kolstad

Reply to
Joel Kolstad

The TIRIS toll tag system uses reflective backscatter and has a range of greater than 30 feet.

The TAG would be on the pole and the ILLUMINATOR would be on the train. TAG battery life would be on the order of

5 years.

AMTEL also makes a similar system. However, the AMTEL tag is on continuously, and may not have as long a battery life, tho I am not certain what they claim.

However, the GPS suggestion which a respondent posts later in this thread is a great idea. It is used by many many transportation agencies, and will have much less cost, as well as not requiring any maintenance on telephone poles. Many railroads do not have telephone poles, anyway --- that stuff is moving underground....

If you are bound and determined to use an RFID tag, I suggest you do a search on SAVI, TIRIS, MARK6 , and SIRIT .

Lots of info available from these companies.

Andy ( formerly principal engineer of TIRIS for Texas Instruments in a previous life )

Reply to
Andy

I seem to remember a system where the RFID tags were attached to the RR tracks at known locations and when the RR went over it, the Tx in the RR triggered the passive tags and they sent an ID back to the train.

This system, using passive tags, will last a heck of a long time, and with the tag so close to the Tx, there is plenty of power to activate the tag.

So, I'd forget the phone poles, burying the tags inside the RR tracks will protect the tags, and use a standard Tx to interrogate them.

=====================

Granted, GPS and a link back to the Hq makes more sense in general, you could have the system auto dial a cellphone and send it's location and time once an hour, or as often as desired.

Jim

Reply to
Jim

if Jim's sugestion is too turn key, Atmel has tags that you can suff in the NEMA box of your choice. Even listed in Digikey.

Cheers

Reply to
Martin Riddle

At the risk of some flameage, we (among others) make turnkey tracking solutions (uses GPRS to report data from GPS amongst other things). Note we're in the UK. I know there are outfits that do this in the states, though.

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Cheers

PeteS

Reply to
PeteS

Considering how cheap a GPS receiver is these days, surely that *has* to be the best option ?

Over here, Woolworths are selling a GPS based 'speed trap detector' for a mere £80 that includes the first years worth of database updates !

It has a GPS data output to connect to a PC / laptop too.

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Graham

Reply to
Pooh Bear

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