Sensor to identify presence of specific physical thing inside or outside of the boundary like shopping mall

[Prashant_9641]

I'm particularly looking for a sensor that can sense a specified (only defined) physical Quantity whether it's in inside or the outside of defined imaginary boundary.

 

[COLGeek]

MERGED QUESTION
Question from Prashant_9641 : "Sensor to identify presence of specific physical thing inside or outside of the boundary like shopping mall"

I'm particularly looking for a sensor that can sense a specified (only defined) physical Quantity whether it's in inside or the outside of defined imaginary boundary.

 

[Alabalcho]

You have to be more specific about what you want to sense. There's no universal solution to your question.
- Can you attach a tag to that object?
- If not, what this object can be sensed with? Light? Capacitance?

 

[USAFRet]

MERGED QUESTION
Question from Prashant_9641 : "How to sense a physical Quantity whether it's inside or outside of defined boundary."

I want to know how can I sense a certain physical Quantity (like human leg or anything else) is within the boundary and touching the ground or its in the air.
The sensor which can only sense that physical entity when it's touching the ground.
For instance, if I plant a proximity sensor at 3 ft. Distance. Now I want to sense only those specific thing which are touching the ground. Can I use a sticker which is used in shopping mall to detect stollen goods.? If I use such sticker to human's shoe it have to tell(signal) me whether men's leg(shoe) is within that 3ft. Boundary or its short of boundary or its inside the three feet but not on the ground. It should give only that signal that the shoe is inside 3 ft boundary and on the ground as well.

Hope this will surve you what I'm imagining.
Please suggest me whole sensor system along with appropriate programme.

Thank you .
Regards,
Prashaant.

Use a laser measuring tool

You did not answer my question in the other thread you've started, and posted a new one.

Your question is to broad to answer. If you want to detect when a human steps within a boundary - make a sensor which will make a contact whenever it is stepped onto. Or put a light barrier around the perimeter, one centimeter off the ground. Or make that person wear reflective socks, and use laser beam with a sensor. Or use an array of proximity sensors, calibrated to desired distance. Or pull a thin wire around the perimeter, and make that person cut thru it. Or...

In end of all - what's the purpose of this system>

MERGED QUESTION
Question from Prashant_9641 : "How to sense a physical Quantity whether it's inside or outside of defined boundary."

I want to know how can I sense a certain physical Quantity (like human leg or anything else) is within the boundary and touching the ground or its in the air.
The sensor which can only sense that physical entity when it's touching the ground.
For instance, if I plant a proximity sensor at 3 ft. Distance. Now I want to sense only those specific thing which are touching the ground. Can I use a sticker which is used in shopping mall to detect stollen goods.? If I use such sticker to human's shoe it have to tell(signal) me whether men's leg(shoe) is within that 3ft. Boundary or its short of boundary or its inside the three feet but not on the ground. It should give only that signal that the shoe is inside 3 ft boundary and on the ground as well.

Hope this will surve you what I'm imagining.
Please suggest me whole sensor system along with appropriate programme.

Thank you .
Regards,
Prashaant.

Use a laser measuring tool

You did not answer my question in the other thread you've started, and posted a new one.

Your question is to broad to answer. If you want to detect when a human steps within a boundary - make a sensor which will make a contact whenever it is stepped onto. Or put a light barrier around the perimeter, one centimeter off the ground. Or make that person wear reflective socks, and use laser beam with a sensor. Or use an array of proximity sensors, calibrated to desired distance. Or pull a thin wire around the perimeter, and make that person cut thru it. Or...

In end of all - what's the purpose of this system>

 

[USAFRet]

Please....let's keep this to ONE thread.
OK?

 

[USAFRet]

I'm particularly looking for a sensor that can sense a specified (only defined) physical Quantity whether it's in inside or the outside of defined imaginary boundary.

Radar, sonar, laser...which of those technologies does not work for you?

 

[Prashant_9641]

My project is much similar to shoplifting detection system. Im planning to attach a sticker (like shopping mall does) to shoes or other things which I perticularly want to measure within or outside of defined line.
If the leg (shoe) is out side of the line the alarm or signal should go to the computer along with impeccable precision.

 

[USAFRet]

My project is much similar to shoplifting detection system. Im planning to attach a sticker (like shopping mall does) to shoes or other things which I perticularly want to measure within or outside of defined line.
If the leg (shoe) is out side of the line the alarm or signal should go to the computer along with impeccable precision.

"impeccable precision" is a very imprecise requirement.
Millimeter, meter, polling frequency, number of items to be tracked...

 

[Karadjgne]

No such beast exists. Not for a centrally located system anyways. To do what you are specifying, you'd need doorway mounted sensors running a positive-negative polarity, and the sticker would have to be designed in such a way as to take that charge and create a signature signal that would be detected. Area broadcast won't work because of signal strength loss with range, there's no guarantee the signal would remain perfect anywhere near the door. Nothing is impeccable, can't count the amount of times the cashier in Home Depot has scanned the magnet tag only for the stupid alarm to then go off as I walk out the door. I did a job in a ladies boutique on time and the alarm went off as my boss walked out. Turned out 15minutes later he was innocent of any shoplifting when the security guard finally found an old magnet strip buried in the bottom of an unused pocket of his tool case. So your special sticker would need to be totally different than any other manufacturers, would need to be physically placed by your employees in such a fashion as to not be easily removable, would have to be strong enough to bypass clothing or other obstacles like purses or bags yet weak enough not to trip the alarm when shoppers walk past the sensor while browsing.

Impeccable isn't feasible.