motion detection the easy way

Archiver

I have a box enclosed on all but one side. I want to be able to send
a signal to my stamp if someone reaches into the box. What is the
easiest and cheapest way to do this, with emphasis on easy. I'm not
an electronics whiz. Any suggestions welcome.

Thanks!

Mark

Archiver

Make two opposite sides of the box two plates of a capacitor in an
RC oscillator where C is the "box-Capacitor". As a person reaches
into the box you should be able to detect a noticable difference
(drop) in frequency. Have the stamp monitor the frequency, If it
falls below a certain threshold then sound an alarm or whatever.

R
o--/\/\--o
| |
| |\ |
o--| \o--o---> Out
| 1|/ 2
|
o

---

||

---

> GND
"box-C"

Note: Use an 74HC14 HEX inverter and tie ALL unused inputs to GND.


This schematic on my website might also be helpful...

http://home.earthlink.net/~y2kbc/Electronics

http://home.earthlink.net/~y2kbc/Electronics/BasicStamp/Coilread.gif

...replace the "coil" with a fixed value resistor or adjustable pot, and
use the "box-Cap" in place of the capacitor


>I have a box enclosed on all but one side. I want to be able to send
>a signal to my stamp if someone reaches into the box. What is the
>easiest and cheapest way to do this, with emphasis on easy. I'm not
>an electronics whiz. Any suggestions welcome.
>
>Thanks!
>
>Mark

---

Beau Schwabe IC Mask Designer
National Semiconductor Wired Communications Division
500 Pinnacle Court, Suite 525 Mail Stop GA1 Norcross, GA 30071

---

Archiver

I would use one of the GPR200 series sensors. They cost around $25 but are
EASY to implement and will be 99.9% reliable. They have a simple digital
output. Depending on the model either a variable output or a single on/off
output.
next simplest may be an IR detector, and a 555 timer to generate the 38,000
khz signal. If you have the stamp I/O capability, and can wait in a loop
until detection, you can generate the 38,000 KHZ from the stamp itself, and
then use a Radio Shlock Tin car IR detector module $5
Have fun.
Sincerely
Kerry
Admin@M...
WWW server hosting [url=Http://mntnweb.com]Http://mntnweb.com[/url]
Kerry Barlow
p.o. box 21
kirkwood ny
13795

Archiver

List suggestions:

If you ever recommend a product- post a source along with the
recommendation-so simple, yet so effective!

If you ever recommend a web site - post the url along with the
recommendation-so simple, yet so effective!



Ken Ambrose



with enough thrust, pigs fly just fine.





---- On Thu, 28 Jun 2001, Kerry Barlow (admin@m...)
wrote:

> I would use one of the GPR200 series sensors. They cost
around $25 but
> are
> EASY to implement and will be 99.9% reliable. They have a
simple digital
> output. Depending on the model either a variable output or a
single
> on/off
> output.
> next simplest may be an IR detector, and a 555 timer to
generate the
> 38,000
> khz signal. If you have the stamp I/O capability, and can
wait in a loop
> until detection, you can generate the 38,000 KHZ from the
stamp itself,
> and
> then use a Radio Shlock Tin car IR detector module $5
> Have fun.
> Sincerely
> Kerry
> Admin@M...
> WWW server hosting [url=Http://mntnweb.com]Http://mntnweb.com[/url]
> Kerry Barlow
> p.o. box 21
> kirkwood ny
> 13795
>
>
>
>
> To UNSUBSCRIBE, just send mail to:
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>
>

Archiver

>I have a box enclosed on all but one side. I want to be able to send
>a signal to my stamp if someone reaches into the box. What is the
>easiest and cheapest way to do this, with emphasis on easy. I'm not
>an electronics whiz. Any suggestions welcome.
>
>Thanks!
>
>Mark

Hi Mark,

You might check out the charge transfer proximity sensors at:
http://www.qprox.com/
These make easy proximity sensitive lamps, faucets, and pushbuttons.
They have an evaluation board available for about $15.

-- Tracy

Archiver

If this is a safety-type application, where somebody could be seriously
injured or worse, be very careful in your selection of a method. In some
cases, only a safety light curtain should be used. These are designed to
be control reliable and have built in redundancy. Unfortunately these
are quite pricey. A 24" STI light curtain is about $2k. Other
manufacturs include Banner and I think Allen-Bradly now carries the
Guardmaster (??) line of light curtains.

If you don't care about safety, maybe you could hack one of thoose motion
lights that you can buy to hang outside above your garage, etc. Seems I
remember a thread on this a long time ago.

Aaron

On Wed, 27 Jun 2001 21:13:46 -0700 markallen <markallen@m...>
writes:
> I have a box enclosed on all but one side. I want to be able to send
> a signal to my stamp if someone reaches into the box. What is the
> easiest and cheapest way to do this, with emphasis on easy. I'm not
> an electronics whiz. Any suggestions welcome.
>
> Thanks!
>
> Mark

Archiver

>
>If you don't care about safety, maybe you could hack one of thoose motion
>lights that you can buy to hang outside above your garage, etc. Seems I
>remember a thread on this a long time ago.

Yup, that's what I ended up doing. Easy and cheap. Incidentally, you
can change how long the sensor stays on by popping it open and
replacing a resistor with one of lower value. Anyone who wants the
details can email me.

Thanks for the tip,

Mark