Impact sensor?

[kyle27012321]

Hey there, I’m trying to find a component able to measure impact with in a particular space confine...

I am trying to measure the impact of a cue tip on a cue ball, I’ve thought of accelerometers but without a set distance I don’t know how this would work, the sensor needs to be > 2 mm at the sensor end and able to measure acceleration and impact pressure.

I have looked at piezo electric pressure sensors, but integration to a circuit is something I’m struggling with.

Ideally all the electronics would be within the cue as it will be hollow and reinforced with a lot of space for circuitry.
Any help would be greatly appreciated.

Thanks
Kyle

 

[(*steve*)]

What are you trying to measure?

Pressure? (use a sensor in the cue tip)
Speed? (use high sped photography)
Energy transfer? (measure weight of ball and from velocity you can calculate this)

Or something else...?

 

[kyle27012321]

I'm trying to measure the impact pressure.. so a sensor in the tip... But what sensor ?

 

[(*steve*)]

I'm not sure. But now we know what you're trying to measure, it seems that a sensor on the cue is what you're after.

Anything I say here is conjecture -- I'm no expert.

My understanding is that a piezo sensor essentially has an output that is proportional to rate of change rather than being an absolute measure.

This means you could capture the waveform created (say on a storage scope) and apply various transforms to it to determine pressure from the rate of change information.

A question is whether you would want the sensor in front or behind the tip, since the tip has some "give" in it. Presumably it would be in front of it.

From my "mis-spent youth" I can tell you that having something with a reduced coefficient of friction on the tip of the cue is going to cause problems, but presumably you're not planning any trick shots.

 

[Laplace]

What you need is a dynamic load cell. http://www.omega.com/pptst/dlc101.html

Don't you normally find a leather pad on the head of a pool cue? Since leather is compressible it will absorb a lot of the impact force and change the peak value. So be sure to mount the impact sensor behind the pad. It might be better to construct a custom impact sensor from two metal disks with piezo crystal between them. Google will show how to grow your own crystal. Then I would just connect the sensor to a digital storage oscilloscope triggered for one-shot recording to get the impact curve.

 

[jackorocko]

Don't you normally find a leather pad on the head of a pool cue?

Yes and they have a variety of tips you can buy. You can buy hard tips that make a tinking noise when striking cue balls. If absorption of the impact is not needed then look to buy a harder tip. I think they even have some made out of plastic these days.