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bill190
01-29-2012, 02:21 AM
Someone gave me a radar speed measuring gizmo. It is intended to measure the speed of a bat swing for baseball or a golf swing.

I'm experimenting with measuring billiard ball speed.

Anyway my home security system has microwave motion sensors and these are making the radar gizmo go haywire!

So I am trying to block the security system motion sensors with aluminum foil. I do this, then the speed measuring gizmo stops blinking, but it is not measuring the speed of anything.

So should I be able to block radar signals with aluminum foil around the motion detector? Or would some of the signal leak out the back? Or through the aluminum foil?

And could another motion detector in another room be leaking signals through a door or wall? (Not covered with aluminum foil.)

I don't know a thing about radar signals!

Phil Pilgrim (PhiPi)
01-29-2012, 02:39 AM
Why not just turn off the security system while you're experimenting?

-Phil

ElectricAye
01-29-2012, 03:06 AM
... then the speed measuring gizmo stops blinking, but it is not measuring the speed of anything....

Are you sure that your radar speed gizmo isn't malfunctioning on its own? perhaps an intermittent failure? I would think metal foil would block any such radar waves.

Also, are you absolutely certain that your home security system is using radar and not passive infrared (PIR)? Most home security systems use PIRs.

Have you tried this speed gizmo someplace away from your house, etc.?

bill190
01-29-2012, 03:09 AM
Why not just turn off the security system while you're experimenting?

The motion detectors are always powered up even when the system is off.

I can power it totally off, but sometimes powering it back on causes memory glitches and it requires re-programming. (Not fun with this old system!)

And also I am curious about radar signals.

bill190
01-29-2012, 03:17 AM
Are you sure that your radar speed gizmo isn't malfunctioning on its own? perhaps an intermittent failure? I would think metal foil would block any such radar waves.

Also, are you absolutely certain that your home security system is using radar and not passive infrared (PIR)? Most home security systems use PIRs.

Have you tried this speed gizmo someplace away from your house, etc.?

OK, just wanted to be sure the aluminum foil should block the signals.

The next question is how far would home security motion detector signals travel? I did try it outside, but neighbors have systems as well. I will try further away.

FYI - I have "dual" PIR/Microwave motion detectors. There must be a PIR AND a Microwave motion detected before it trips the alarm. This prevents false alarms which are common with just a microwave unit or just a PIR unit.

DavidSmith
01-29-2012, 04:26 AM
Bill190,

Test your gun outside on something else. Also, read the specs. I once tried to use a bullet speed detector to test arrows. Should have worked, it would only require some math to adjust for an arrow being longer than a bullet. Git bizarre results. Finally figured out the detector was not designed to handle anything as slow as an arrow and was resetting several times while still trying to measure an arrow still in the sensor path.

Also, billiard balls? Smooth rounded surface. SHOULD reflect a nice echo, but not guaranteed. What frequency does the thing use, and remember you cannot measure anything w a wavelength greater than the object.

bill190
01-29-2012, 06:07 AM
This is just a cheapie. The instructions don't say what frequency.

I tried further away, but still not working. Tomorrow I'll go out in the woods and see if it works out there...

Heater.
01-29-2012, 08:04 AM
Isn't a billiard ball rather transparent to radar what with being made of plastic?

bill190
01-29-2012, 04:57 PM
Isn't a billiard ball rather transparent to radar what with being made of plastic?

The ball to measure speed would be the white cue ball and "breaking speed".

And white cue balls are of 3 different types.

-Just phenolic resin.
-Metal particles added.
-Magnet added.

The metal particles added and magnet added types of cue balls are used in bar coin operated pool tables. There is a mechanism in these which will divert the cue ball to come out a different opening.

On a rail inside the table, where the balls roll along, there is a large magnet to one side. As the balls roll by, the balls with no metal or magnets continue in a straight line. The cue ball with metal in it or a magnet is pulled to one side and then goes into a different track, and then comes out the different opening.

Some cheap bars have cue balls which are larger in diameter than the other balls. These are not magnetic nor do they contain metal. For those balls, there is a piece of metal above the balls and this is at a height which will allow the smaller balls to pass under it, but the larger ball will be diverted by the metal bar to the other track.

Cue balls which are larger in diameter than the other balls are TERRIBLE to play with as they are a different size and weight than the balls they are hitting.

The cue balls with a magnet in them might not roll true, thus the balls with metal particles distributed throughout are better.

Quality "tournament" cue balls which are the exact size and weight of the other balls are manufactured by Saluc/Aramith - Belgium...
http://www.saluc.com/html/billiard/index.php

A pool table manufacturer called "Diamond" makes a bar table with an optical sensor for this...
["Patented optical density sensor built into the ball return system. Allows the player to use super Aramith Pro BallsŪ with the red circle cue ball. No longer do the amateurs have to play with an oversized or magnetic cue ball."]
http://www.diamondbilliards.net/CommercialTables/SmartTable/tabid/70/Default.aspx

Heater.
01-29-2012, 05:51 PM
Bill,

Well you learn something new everyday. Thanks. seems I don't hang around in bars enough:)

skylight
01-29-2012, 06:06 PM
Sounds like a job for the ColorPal (http://www.parallax.com/StoreSearchResults/tabid/768/txtSearch/colorpal/List/0/SortField/4/ProductID/617/Default.aspx) regarding the billiard balls

bill190
01-29-2012, 08:13 PM
Well I drove away from my area and the radar gizmo worked OK, but within 2 miles of my house it does not work. (I've had trouble with wireless devices not working in my area too.)

skylight
01-29-2012, 09:11 PM
Do you live near any military installations?

bill190
01-30-2012, 12:28 AM
No.

There is just private 2-way radio, wireless internet, cell phone, and repeaters for whatever on a hill around here.

Gadgetman
01-30-2012, 08:42 AM
A couple of questions...

1. Are you certain that your Home Security system uses microwaves?
I would rather expect it to use ultrasound, not microwaves for motion detection.

2. how fast does a billiard ball move? It may be too slow for the radar to handle?

3. Are you certain it's really a radar and not just a PING in a pretty package? ;-)

bill190
01-30-2012, 05:35 PM
1. Are you certain that your Home Security system uses microwaves?
I would rather expect it to use ultrasound, not microwaves for motion detection.

Yes. I ordered the motion detectors and installed them myself.

FYI - To my knowledge "ultrasonic" motion detectors are rarely used anymore for security systems. "Expansion valves" in compressed refrigerant systems like refrigerators, water coolers, and air conditioning systems will emit ultrasonic sounds and make these false alarm.



2. how fast does a billiard ball move? It may be too slow for the radar to handle?

For a break shot, about 20 to 30 mph. And note for the fastest break shot, you would be accelerating your arm faster and faster as the cue stick approaches the cue ball. So the cue stick would be going the fastest in the final inch of hitting the cue ball.

So not easy to measure the speed of the cue stick. And the billiard ball only travels a short distance before hitting the rack. That makes speed measurement difficult as well.

I did read that more expensive better quality "radar guns" work the best for measuring this. And I read that some of the less expensive radar guns only work half the time.

So far as using my radar gizmo for pool, I only tried a few shots and saw it was not working. Then tried placing reflective metal on the cue stick and that worked about 10% of the time if I was swinging it like a bat past the gizmo.

So then I tried other tests. Waving metal objects past it fast. It rarely worked.

Then I drove away from my home. About two miles away I could drive past metal signs going 20 to 45 mph and it would work all the time.

But when I got to within 2 miles of my house, it stopped working.




3. Are you certain it's really a radar and not just a PING in a pretty package? ;-)

Yes. It says "Radar" on it. Also when I place it in the same room as a motion detector, it constantly blinks and shows various speeds. When I place aluminum foil over the motion detector, it stops blinking.

Bottom Line: Someone gave me this gizmo. I have no need to measure pool break speeds. It just would have been interesting to see what various speeds were as compared with the spread of the balls on the table after a break. So I will place it in my electronics pile...