To catch a thief

nippip

Where I work there is a common kitchen and peoples lunches are disappearing regularly. I was thinking of putting some RFID tags on some tasty lunch items and have a reader that would work if I just walked by the culprits office i.e. I need good distance.
If you have suggestions on how better to do this or have links on a DIY reader and where to get tags I would greatly appreciate it.

$WMc%

The range on the RFID tags aren't long enough for this application.
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I would look into a miniature wireless camera watching the kitchen. Hide or cancel the camera.
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The little camera I have will run all day long on one 9volt battery.(about 8 hours) It also has audio.
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The camera is about 1"h x 1"w x 3/4"deep
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http://www.spyville.com/mini-wireless-spy-cam.html
SV-DDMINI $89.00

Leon

In the lab where a cousin of mine once worked, many years ago, someone was stealing the milk. They laced a bottle with phenolphthalein, which was used as a chemical indicator, but is also a very powerful laxative. They didn't lose any more milk. I wouldn't try that sort of thing these days, the police would probably get involved.

nippip

$WMc% wrote: »

The range on the RFID tags aren't long enough for this application.

I really know nothing about RFID's but I did see a thread where they were talking about powered RFID tags which could be read from 20 feet or so. Would something like this work???

$WMc%

nippip wrote: »

I really know nothing about RFID's but I did see a thread where they were talking about powered RFID tags which could be read from 20 feet or so. Would something like this work???

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I would like to see this thread.
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If it has 20 feet of so of range. I think it would be ideal for your application.
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In my experience, I have found that even the commercial RFID tags used for retail stores only have a range of 6 to 12 inches max. But I'm not an expert on RFID tags and readers.
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If you have found an RFID tag reader with a 20 foot range, Please share this with us here on the forums. Thanks
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I would be happy to help you with any coding issues you have.

blittled

There are two types of RFID, passive and active. Passive doesn't require power for the tags and may have a range of 6" or so. Active are powered and can have any range. Some active ones use GPS for tracking. The passive tags are inexpensive while the active are relatively expensive.

nippip

blittled, thanks for the term "active tag". I was able to find the following the following from the RFID Journal;

Active tag: An RFID tag that has a transmitter to send back information, rather than reflecting back a signal from the reader, as a passive tag does. Most active tags use a battery to transmit a signal to a reader. However, some tags can gather energy from other sources. Active tags can be read from 300 feet (100 meters) or more, but they're expensive (typically more than US$20 each).

300 feet would be too powerful for my needs but maybe the battery assisted passive or "BAP" tags would do the job. If I could pick up a signal when walking past someone's office with the tag in there office that would be perfect.

I was thinking I could make a DIY reader but could use tips on that as well.

$WMc%, thanks for the offer with coding. I really am a fish out of water here

$WMc%

I didn't know of Active RFID tags or Passive assisted tags.
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Have you found a BAP tag thats cost effected for your project ?
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If so, does it give info on what the DATA packet looks like ?
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This might be just a re-write of the code that the Parallax RFID reader needs to use these BAP tags.
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I think we could all use a little more range from an RFID tag.

Franklin

http://www.zigbeef.com/