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PICList Thread
'Object Speed Counting in sunlight.'
1998\11\12@145408 by Mike Chaloupka

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Suggestions anyone?

I have been monitoring mail traffic for IIR, Laser diode or Ultrasonic suggestions that my be able to solve my problem.

I need to detect the speed of an object 2 - 5 feet from the sensor mount.  

Sensor is mounted upward looking at the sky.  

My thought was to use two ultrasonic sensors to detect a pulse width to determine the time the object was within the cone.  

Range data is secondary if  at all.

Need to be inexpensive - doesn't it all....

Suggestions / contacts are greatly appreciated...

Thanks

Mike
Control System Research

1998\11\12@152925 by Andy Kunz

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>I need to detect the speed of an object 2 - 5 feet from the sensor mount.

Obviously you aren't flying F3E!

Andy


==================================================================
Andy Kunz - Statistical Research, Inc. - Westfield, New Jersey USA
==================================================================

1998\11\12@160024 by goflo

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F3E?

Andy Kunz wrote:
>
> >I need to detect the speed of an object 2 - 5 feet from the sensor mount.
>
> Obviously you aren't flying F3E!
>
> Andy
>
> ==================================================================
> Andy Kunz - Statistical Research, Inc. - Westfield, New Jersey USA
> ==================================================================

1998\11\12@164325 by Engineering Department

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<Mike Chaloupka writes in part>

>I have been monitoring mail traffic for IIR, Laser diode or Ultrasonic
suggestions that my be able to solve my problem.
>I need to detect the speed of an object 2 - 5 feet from the sensor mount.
>Sensor is mounted upward looking at the sky.

Why not use the Sun's IR?  I have no idea if this would work; but, adjust
the bias on an IR detector until it just trips a Schmidt trigger in open
sunlight.  When the object passes overhead it will (presumably) obscure the
sun.

Putting a second detector in the line of travel will give a second pulse
that confirms the validity of the first one and could be used for speed
calculations if the geometry is right.

Granted it's downright ugly, but it sure is cheap <g>.

Cheers,

Win

1998\11\13@053133 by Peter L. Peres

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On Thu, 12 Nov 1998, Mike Chaloupka wrote:

> I need to detect the speed of an object 2 - 5 feet from the sensor mount.
>
> Sensor is mounted upward looking at the sky.

The optical way is easy, using a CW light source in the night and the sun
in the day, but one uses more than one sensor (more like a matrix -
minimum size 2 x 2) connected to a micro. This eliminates dirt etc sensing
and can tell which way the object is passing, also has an early failure
indicator built-in (sensors won't fail together unless someone paints
them over very quickly <g>).

I did something similar for a protection device on an exhaust chimney and
I used 4 Al. tubes of different lengths in a pipe-organ style mount with
glass windows and CdS photoresistors at the bottom connected to a LM324.
The LM324 was connected as adaptive AC amplifier (to remove DC bias). The
light was a parlight and was on all the time with a current sense resistor
in one of the return wires. Outputs went to a Z80 based controller that
also did other things.

hope this helps,

Peter

1998\11\19@130333 by Peter L. Peres

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On Thu, 12 Nov 1998, Mike Chaloupka wrote:

> I need to detect the speed of an object 2 - 5 feet from the sensor mount.
>
> Sensor is mounted upward looking at the sky.

The optical way is easy, using a CW light source in the night and the sun
in the day, but one uses more than one sensor (more like a matrix -
minimum size 2 x 2) connected to a micro. This eliminates dirt etc sensing
and can tell which way the object is passing, also has an early failure
indicator built-in (sensors won't fail together unless someone paints
them over very quickly <g>).

I did something similar for a protection device on an exhaust chimney and
I used 4 Al. tubes of different lengths in a pipe-organ style mount with
glass windows and CdS photoresistors at the bottom connected to a LM324.
The LM324 was connected as adaptive AC amplifier (to remove DC bias). The
light was a parlight and was on all the time with a current sense resistor
in one of the return wires. Outputs went to a Z80 based controller that
also did other things.

hope this helps,

Peter

1998\11\21@105054 by Mike Chaloupka

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Thanks Peter for the tip.  Any suggest regarding the light source.  I though of using an EGG laser diode / receiver but total component cost are toooo high.  

Regarding the photoresistor - any particular kind?  

Did I mention the projectile my be travelling upto 100mph and has a width 4-5 inch circular & 19 inch long...  

Have you or anyone else listening hear dir MIR  Mircropower Inpulse Radar technolgy.  FCC doesn't like it yet buy companies have spend a lot for the license to use the technology.   I understand it will revolutionize speed & object sensing since the entire circuit (transmitter /receiver) is possible under $50

Mike

>>> "Peter L. Peres" <spam_OUTplpTakeThisOuTspamACTCOM.CO.IL> 11/13 5:34 AM >>>
On Thu, 12 Nov 1998, Mike Chaloupka wrote:

> I need to detect the speed of an object 2 - 5 feet from the sensor mount.
>
> Sensor is mounted upward looking at the sky.

The optical way is easy, using a CW light source in the night and the sun
in the day, but one uses more than one sensor (more like a matrix -
minimum size 2 x 2) connected to a micro. This eliminates dirt etc sensing
and can tell which way the object is passing, also has an early failure
indicator built-in (sensors won't fail together unless someone paints
them over very quickly <g>).

I did something similar for a protection device on an exhaust chimney and
I used 4 Al. tubes of different lengths in a pipe-organ style mount with
glass windows and CdS photoresistors at the bottom connected to a LM324.
The LM324 was connected as adaptive AC amplifier (to remove DC bias). The
light was a parlight and was on all the time with a current sense resistor
in one of the return wires. Outputs went to a Z80 based controller that
also did other things.

hope this helps,

Peter

1998\11\21@201047 by Mark Willis

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Hosfelt electronics (http://www.hosfelt.com/) has hand-held laser
pointers for as little as $10.95 USD, you could adapt one to a "wall
wart" power source, I'd guess.  Some decent prices on other goodies for
PICers, too, there.  White LED's pricing looked pretty OK, for one.

 Inquiring Minds wanna know:  What in the world's that projectile?  Are
you making a "Poor Man's Howitzer" here or something?  <G>

Mike Chaloupka wrote:
>
> Thanks Peter for the tip.  Any suggest regarding the light source.  I though o
f using an EGG laser diode / receiver but total component cost are toooo high.
>
> Regarding the photoresistor - any particular kind?
>
> Did I mention the projectile my be travelling upto 100mph and has a width 4-5
inch circular & 19 inch long...
>
> Have you or anyone else listening hear dir MIR  Mircropower Inpulse Radar tech
nolgy.  FCC doesn't like it yet buy companies have spend a lot for the license t
o use the technology.   I understand it will revolutionize speed & object sensin
g since the entire circuit (transmitter /receiver) is possible under $50
{Quote hidden}

1998\11\22@112756 by Peter L. Peres

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On Sat, 21 Nov 1998, Mike Chaloupka wrote:

> Thanks Peter for the tip.  Any suggest regarding the light source.  I
> though of using an EGG laser diode / receiver but total component cost
> are toooo high.

A parlight is a parlight. Made by GE, available through any party/show
lighting supply.

> Regarding the photoresistor - any particular kind?

I used plain CdS photocells (the uncased version - a disc with 2 terminals
protruding on the back).

> Did I mention the projectile my be travelling upto 100mph and has a
> width 4-5 inch circular & 19 inch long...

No you did not. This may be a problem... My pipe organ had 2/3 tubes so
it's up to you to calculate how long they will be obscured / lighted,
each, at 100 mph and make sure that your electronics will be up to the
task.

Makes me wonder what you're counting ?!

Peter

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