# Speed measurement help

Y

#### Yen Pham

Jan 1, 1970
0
Hi,

Can someone points me in the right direction with this problem. I need to
buy a calibrated device that can measure the speed of an object to within
+/-1%. The object is fairly small at about 3" diameter and moving at about
150mph in a known path. Is there something like a calibrated laser speed
trap that I can buy from somewhere that will give me these measurements? We
don't really have time to engineer something at the moment, so an off the
shelf solution would be perfect. Your assistance is greatly appreciated.

Yen

R

#### Repeating Decimal

Jan 1, 1970
0
Hi,

Can someone points me in the right direction with this problem. I need to
buy a calibrated device that can measure the speed of an object to within
+/-1%. The object is fairly small at about 3" diameter and moving at about
150mph in a known path. Is there something like a calibrated laser speed
trap that I can buy from somewhere that will give me these measurements? We
don't really have time to engineer something at the moment, so an off the
shelf solution would be perfect. Your assistance is greatly appreciated.

Yen
If you don't have time to engineer, why would you expect someone else, who
is not a vendor, to do it for you. If I knew, without search or effort where
you could get one, I might happily let you know. If I did that kind of
consulting for a living, I would quote you a price. But I do not.

Bill

L

#### Louis Boyd

Jan 1, 1970
0
Yen said:
Hi,

Can someone points me in the right direction with this problem. I need to
buy a calibrated device that can measure the speed of an object to within
+/-1%. The object is fairly small at about 3" diameter and moving at about
150mph in a known path. Is there something like a calibrated laser speed
trap that I can buy from somewhere that will give me these measurements? We
don't really have time to engineer something at the moment, so an off the
shelf solution would be perfect. Your assistance is greatly appreciated.

This uses microwaves rather than lasers but it looks like it will do
what you want quite nicely.

Accuracy ± 0.1 MPH
Speed Range 1-300 MPH
Target Acquisition Time 0.01 Seconds
Microwave System Ka Band, 20 mw
Weight 3.2 Pounds
Data Output TTL and RS-232
Output Sample Rate 31.25 Per Second
Display Units MPH, KPH and Knots
Estimated Range (baseball) 450 feet
Price $2500. G #### Ghost Chip Jan 1, 1970 0 O #### Opto Jan 1, 1970 0 Repeating Decimal said: If you don't have time to engineer, why would you expect someone else, who is not a vendor, to do it for you. If I knew, without search or effort where you could get one, I might happily let you know. If I did that kind of consulting for a living, I would quote you a price. But I do not. Bill Bill, For pete's sake, lay off the guy, would you? People ask for vendor recommendations quite often on newsgroups. You need to learn to relax a little bit. Opto F #### Fred Bloggs Jan 1, 1970 0 This uses microwaves rather than lasers but it looks like it will do what you want quite nicely. http://www.radarsport.com/equipmentStalker.html Accuracy ± 0.1 MPH Speed Range 1-300 MPH Target Acquisition Time 0.01 Seconds Microwave System Ka Band, 20 mw Weight 3.2 Pounds Data Output TTL and RS-232 Output Sample Rate 31.25 Per Second Display Units MPH, KPH and Knots Estimated Range (baseball) 450 feet Price$2500.
Also from the same manufacturer:
"Many may not understand why radar performance and clocking distance is
so important. To get correct readings, a radar needs to be placed in the
line of travel of objects (it cannot clock objects at angles or as they
go by). In the real world, the radar gun needs to be placed far away
from the target. That is why Stalkers are designed to provide
extraordinarily long clocking range. "

So that 1% accuracy implies cos(a)>=0.99 or less than 8 degrees
deviation from velocity angle.

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