Movement sensor
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Posts: 46,084
I'm looking for some form of movement sensor to use with my stamp
project.
Imagine a window frame (made of wood, metal, plastic, the material
doesn't matter to me) that is 18" wide, 24" high and 3" deep. I want
to sense any movement in that window, say whenever an insect
passes thru the window opening. The sensor field is to be limited to
that window, so that insects hovering just outside the window limts
don't trigger the sensor. I've tried ultrasonic but can't contain it
within the window, it trips when something passes just outside the
window opening. Whatever the sensor is, the field has to trigger only
when something is actually within the window dimensions. I'm not
looking for positional awareness within the window either, just the
fact that movement occurred.
Any suggestions on a sensor that can be set to limit its field of
coverage within those dimensions?
Ray
project.
Imagine a window frame (made of wood, metal, plastic, the material
doesn't matter to me) that is 18" wide, 24" high and 3" deep. I want
to sense any movement in that window, say whenever an insect
passes thru the window opening. The sensor field is to be limited to
that window, so that insects hovering just outside the window limts
don't trigger the sensor. I've tried ultrasonic but can't contain it
within the window, it trips when something passes just outside the
window opening. Whatever the sensor is, the field has to trigger only
when something is actually within the window dimensions. I'm not
looking for positional awareness within the window either, just the
fact that movement occurred.
Any suggestions on a sensor that can be set to limit its field of
coverage within those dimensions?
Ray
Comments
thinking is two or three IR led's oscillating at 40khz and
whatever number of IR sensors also at 40khz, so that all area's
are covered. Maybe hook all of them in parallel so any one would
trip the same input, and have a tight loop or while statement
looking for a change.
Original Message
From: "ac_cars" <w2ec@a...>
To: <basicstamps@yahoogroups.com>
Sent: March 14, 2002 11:02 AM
Subject: [noparse][[/noparse]basicstamps] Movement sensor
I'm looking for some form of movement sensor to use with my stamp
project.
Imagine a window frame (made of wood, metal, plastic, the
material
doesn't matter to me) that is 18" wide, 24" high and 3" deep. I
want
to sense any movement in that window, say whenever an insect
passes thru the window opening. The sensor field is to be limited
to
that window, so that insects hovering just outside the window
limts
don't trigger the sensor. I've tried ultrasonic but can't contain
it
within the window, it trips when something passes just outside
the
window opening. Whatever the sensor is, the field has to trigger
only
when something is actually within the window dimensions. I'm not
looking for positional awareness within the window either, just
the
fact that movement occurred.
Any suggestions on a sensor that can be set to limit its field of
coverage within those dimensions?
Ray
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which reflect stationary LED beams using voice-coil electromagnetic
drivers similar to those used in laser light shows. A recent Nuts N
Volts issue described a project which does this.
If insect detection is the actual problem here, other variables would
apply such as insect opacity, size, air speed, and wing-beat frequency
producing clutter, among others. Bats do an excellent job with
ultrasound, but emulating a bat would push the limits of a DSP chip, and
be way beyond current Stamp capabilities.
Dennis
Original Message
From: Larry Gaminde [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=-bFMjksf7AKd4yBQsOtakTPFJLXhjuUs1q0iNCQpg2nV5hm35cN5EXnjkhuFHc9oQBodKDpaVBVpDOWhXA]lgaminde@t...[/url
Sent: Thursday, March 14, 2002 11:19 AM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] Movement sensor
I've been looking into something close to this, what I was thinking is
two or three IR led's oscillating at 40khz and whatever number of IR
sensors also at 40khz, so that all area's are covered. Maybe hook all of
them in parallel so any one would trip the same input, and have a tight
loop or while statement looking for a change.
Original Message
>From: Larry Gaminde [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=5gED9Q525pO_QRxMcCDcb1c2ZXdx2nNfylMwvy-JFQUyqSqP7ONBGoKpSioV6yw7WqWUGFMrlVHqYQ2daA]lgaminde@t...[/url
>Sent: Thursday, March 14, 2002 11:19 AM
>To: basicstamps@yahoogroups.com
>Subject: Re: [noparse][[/noparse]basicstamps] Movement sensor
>
>I've been looking into something close to this, what I was thinking is
>two or three IR led's oscillating at 40khz and whatever number of IR
>sensors also at 40khz, so that all area's are covered. Maybe hook all of
>them in parallel so any one would trip the same input, and have a tight
>loop or while statement looking for a change.
How big are the smallest insects? Perhaps you could build a frame with a
mirrored strip on the inside top and bottom and insert this into the
window. Shine something like a laser pointer down thru a hole in the top
mirror near one end at an angle that will make it bounce back and forth
between top and bottom mirrors with a spacing that won't let your smallest
bug get by. At the end have a detector. If the bugs break the beam too
quickly to be sure of counting them, stretch the pulse a bit to be sure
it's detected. You'll need to be able to make some sensitive adjustments
to the angle of the mirrors in two dimensions to get that beam to bounce
just so. The mechanicals here aren't simple, but in the end it's simple
beam-break technology. It doesn't get much simpler or more sure than that.
Jim H
the wires,
when a insect flies through, it draws a spark and causes a momentary pulse
that you can count. You can run all vertical or horizontal only wires, and
alternate which ones are hot and the return lines. The nice thing is you
won't have to chase the insects around afterwards either, just sweep them up
or have a tray under it that you can empty from time to time. You can use a
automobile igntion coil and a hi-voltage capacitor bank (if needed) to store
the charge.
You can also just listen for the crack sound when the spark is drawn too. A
simple mic would work.
Original Message
From: Jim Higgins [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=TjN-tDtbw-QTuq5CZqPPcUSnv_wPyx9VY_uAqg-U-TOKwVv1fRtF_zoHb1_KxjCBpv4a-QJem8xx4A]HigginsJ@s...[/url
Sent: Thursday, March 14, 2002 7:50 PM
To: basicstamps@yahoogroups.com
Subject: RE: [noparse][[/noparse]basicstamps] Movement sensor
>
Original Message
>From: Larry Gaminde [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=D6-iMPUY_HK3spaSVHc4KSzreUWWraKbEJueI0gVqd4vZHsylx3AODFYEDA1jMJcxHcozFcPhqcmIn6wPDo]lgaminde@t...[/url
>Sent: Thursday, March 14, 2002 11:19 AM
>To: basicstamps@yahoogroups.com
>Subject: Re: [noparse][[/noparse]basicstamps] Movement sensor
>
>I've been looking into something close to this, what I was thinking is
>two or three IR led's oscillating at 40khz and whatever number of IR
>sensors also at 40khz, so that all area's are covered. Maybe hook all of
>them in parallel so any one would trip the same input, and have a tight
>loop or while statement looking for a change.
How big are the smallest insects? Perhaps you could build a frame with a
mirrored strip on the inside top and bottom and insert this into the
window. Shine something like a laser pointer down thru a hole in the top
mirror near one end at an angle that will make it bounce back and forth
between top and bottom mirrors with a spacing that won't let your smallest
bug get by. At the end have a detector. If the bugs break the beam too
quickly to be sure of counting them, stretch the pulse a bit to be sure
it's detected. You'll need to be able to make some sensitive adjustments
to the angle of the mirrors in two dimensions to get that beam to bounce
just so. The mechanicals here aren't simple, but in the end it's simple
beam-break technology. It doesn't get much simpler or more sure than that.
Jim H
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