Is there a Chrono that utilizes Lasers instead of photo or magneto?

[thegunnerd]

I was thinking today how much i hated regular chronos and trying to use them indoors of course. Yes yes there's a lighting kit etc but that's a pain in the ass.

All this happened when i saw one of those chronos that use magnetic fields and strap onto the end of your barrel ( rifles ) . I thought to myself , why can't you use a laser as the field that the bullet breaks ? In essence the same way that it uses the photo sensor to say , hey it passed here and then measure the time between that and the second pickup.

It seems to me that you could do the same with 2 laser arrays and not need to worry about ambient light or that at all.

So far i haven't seen one that is made for purchase, a few people making their own . I know for a fact that lasers are used in this respect in industrial purposes so why not for us.

I may have to get something started

Aaron

[mpk1996]

the laser is very small and straight beam. it would be very hard to insure that the bullet broke both of the beams.

[thegunnerd]

the laser is very small and straight beam. it would be very hard to insure that the bullet broke both of the beams.

I was thinking of a sort of laser array , and there are ways of making the beam wider using mirrors and lenses .

[RePete]

I wonder if you could setup 2 barcode readers (set to continuous) mas the start and stop sensors?

[thegunnerd]

Kinda like the idea i had in my head . It passes through one array starting a timer which then gets shut off by the other array. Presto you have a muzzle vel as long as you have the exact distance between arrays.

[Zeke013]

Here's one using magnets. http://www.magnetospeed.com/

[Graham Smith]

There is a new chronograph just out but I really don't remember any details other than very expensive. I seem to recall it used acoustics.

[ChuckS]

There is a new chronograph just out but I really don't remember any details other than very expensive. I seem to recall it used acoustics.

There is a device on Ebay. It detects the supersonic shock wave so (on a standard day at sea level) it would not work for anything slower than ~1100 fps.

[RePete]

Oehler had the Model 43 Personal Ballistics Laboratory with acoustic microphone and amplifier. No longer made.

[Classic_jon]

I am making an educated guess here that there are three things involved.

1)cost 2)Safety/regulatory 3)Accuracy

1) Cost

Making an array or making a laser beam "sweep" like a bar code scanner does is expensive and requires calibration from time to time to keep it working correctly. The technology in this has come a long way but there is a reason good bar code scanners are still in the 100+ dollar range each.

2)Safety/regulatory

If you put a "laser" in something it has to comply with all of the safety and regulations necessary because it can blind someone. Basically, it has to have the warning stickers and all of that stuff...which raises #1, costs.

https://www.osha.gov/SLTC/laserhazards/

and

http://www.lasercompliance.com/faq.htm

3) Accuracy

A "laser eye" would not do much better than a regular "photosensor" as they operate on similar principles.

For the use in a Chronograph all the photo-sensor is doing is detecting the "passage" of the object and recording the time it takes to go past two set distance points. Would a laser be more accurate? Yes, but at that point you are talking .1 or less difference in accuracy for a lot more cost.

Another aside is that a "laser" would use more power than a standard photo-sensor but that is minor in what we are talking about.

Again, I am making educated guesses here but it sounds logical to me.

[thegunnerd]

I am making an educated guess here that there are three things involved.

1)cost 2)Safety/regulatory 3)Accuracy

1) Cost

Making an array or making a laser beam "sweep" like a bar code scanner does is expensive and requires calibration from time to time to keep it working correctly. The technology in this has come a long way but there is a reason good bar code scanners are still in the 100+ dollar range each.

2)Safety/regulatory

If you put a "laser" in something it has to comply with all of the safety and regulations necessary because it can blind someone. Basically, it has to have the warning stickers and all of that stuff...which raises #1, costs.

https://www.osha.gov/SLTC/laserhazards/

and

http://www.lasercompliance.com/faq.htm

3) Accuracy

A "laser eye" would not do much better than a regular "photosensor" as they operate on similar principles.

For the use in a Chronograph all the photo-sensor is doing is detecting the "passage" of the object and recording the time it takes to go past two set distance points. Would a laser be more accurate? Yes, but at that point you are talking .1 or less difference in accuracy for a lot more cost.

Another aside is that a "laser" would use more power than a standard photo-sensor but that is minor in what we are talking about.

Again, I am making educated guesses here but it sounds logical to me.

Really , the reason i consider this over photo sensing is the able to use it in any lighting condition as opposed to the current chronos out there.

[Graham Smith]

Here is the one I was thinking about: http://www.steinertsensing.com/pub_docs/files/SuperChrono-Data-Sheet.pdf

Edited July 31, 2013 by Graham Smith

[RePete]

Here is the one I was thinking about: http://www.steinertsensing.com/pub_docs/files/SuperChrono-Data-Sheet.pdf

Looks interesting but at 2495.00 Norwegean Krone ($422.00) it's a spendy little puppy.

.

It only works with supersonic bullets and not sub sonic.

From their web page -

All shots are detected by up to 99.5% accuracy as long as the ball keeps supersonic.

Edited July 31, 2013 by RePete

[Graham Smith]

They are $350 in the US. The supersonic limitation is suitable for rifles, but I think only Open pistols are likely to shoot in that range.

I use a MagnetoSpeed with my rifle and love it, but I have yet to try it with a pistol.

Edited July 31, 2013 by Graham Smith

[Classic_jon]

I am making an educated guess here that there are three things involved.

1)cost 2)Safety/regulatory 3)Accuracy

Really , the reason i consider this over photo sensing is the able to use it in any lighting condition as opposed to the current chronos out there.

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Understood and I see your point, and it is a valid one. If they could get the cost comparative to the cheap electric eyes then I would be all over it for exactly the reasons you list above! :-)

From a manufacturers and price point to the consumer point of view the second you go away from cheap electric eyes then you get into $$. If you can sell 5 of the ones that use the cheap electric eye and know that they are durable, work, and will keep your support/RMA calls down then that is the way they will go. For a laser type setup it will not be as durable, will require calibration, will drive support calls, and will require more RMA work... so they just don't offer them "mainstream"... for the most part.

As an example http://www.williamson-labs.com/chronograph_lt.htm

and

(this one is actually kind of neat ) http://proceedings.spiedigitallibrary.org/proceeding.aspx?articleid=1011161

Edited July 31, 2013 by Classic_jon

[thegunnerd]

I saw those articles , very very cool stuff. The internal ballistics one is fascinating . I hadn't really thought about it before like that. I have such great ideas...... If only they were economically feasible . I now must become independently wealthy and just make prototypes of things for myself . heh