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Force Sensing Resistance in Concrete

I'm looking for an implementation for detecting when a person walks
over given sections of a sidewalk. Digging up and existing sidewalk
to install force sensing resistors may not be an economically viable
solution, however I would like some help in solving this.

I was also thinking of an EMF detection wire system, similar to those
used for vehicle detection on roadways, but to detect people. However,
this would be subject to too much external EMF interference due to
it's highly-sensitive calibration.

Ideas?

Thanks
 
G

G. Schindler

Jan 1, 1970
0
I'm looking for an implementation for detecting when a person walks
over given sections of a sidewalk. Digging up and existing sidewalk
to install force sensing resistors may not be an economically viable
solution, however I would like some help in solving this.

I was also thinking of an EMF detection wire system, similar to those
used for vehicle detection on roadways, but to detect people. However,
this would be subject to too much external EMF interference due to
it's highly-sensitive calibration.

Ideas?

Thanks
If you are trying to apply this to an existing sidewalk it would seem
you're going to be stuck with some sort of proximity detection as
opposed to force sensing.

BTW ... The vehicle detectors I have worked with, like the Peeks, sense
metal and are thus not suitable for sensing people.

Sensing a non-metallic body would likely be best implemented as either a
sense antenna buried next to the sidewalk (assuming that this is
practical) or falling back on tried and true technology like sensing
when an optical beam is broken by the person walking on the target area.
This seems like it would be the simplest and most reliable solution too.

To top it off, you are sure to find lots of optical beam detectors at
you local security dealer, hardware store, or Radio Shack.

I'd try approaching your local security contractor and placing the
problem at their feet.

Or, you could go to your local security hardware dealer and ask what
they might have that would be suitable for localized proximity or motion
detection.

Either of these two suggestions would put you in touch with the people
most likely to get you the answers you need.


That said, if you just want to develop a new product then you might be
able to place small acoustic sensors in the sidewalk (would only need
small holes drilled) and listen for footsteps. I suspect that this
would actually be reasonably practical to develop if there is not a lot
of other noise sources to confuse the sensors. Something like this may
already exist as they use something similar around bank vaults (though
not as sensitive). Again, talk to your security hardware dealer.



Good Luck.
 
J

John

Jan 1, 1970
0
I'm looking for an implementation for detecting when a person walks
over given sections of a sidewalk. Digging up and existing sidewalk
to install force sensing resistors may not be an economically viable
solution, however I would like some help in solving this.

I was also thinking of an EMF detection wire system, similar to those
used for vehicle detection on roadways, but to detect people. However,
this would be subject to too much external EMF interference due to
it's highly-sensitive calibration.

Ideas?

Thanks

Infrared laser beam? (infrared to keep people from playing with a
visible beam)

Simple: Detect a break in the beam across the area of interest.

Complex: Use a *very* narrow laser source on each edge of the sidewalk
aimed at a small reflector on the sidewalk surface between the laser
source and the *very* narrow detector. The weight of a person walking
across the sidewalk would deflect the concrete enough to be detected.
Yes, sidewalks do deflect under a person's weight, just not very much
;-)
 
S

steamer

Jan 1, 1970
0
--Well assuming they're not wearing moccasins howzabout sensing
sound? Shoes tend to "click" and this might be easiest to sense.
 
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