This is topic How to build a bullet sensitive screen? in forum Film-Yak at Film-Tech Forum ARCHIVE.


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Posted by Randy Stankey (Member # 64) on 08-23-2002, 01:01 PM:
 
OK. Sounds really off the wall but here goes.

In the basement of the new house there is enough room to build a home theatre. Sounds great. Good long-term tinkering project.

So I'm talking to Melanie and she says, "Unh Uh! No way! I want an indoor shooting range!" Yes, she likes to target shoot with handguns. Well, It's a small matter to build a bullet trap in the basement out of 1/4 inch or 1/2 inch steel plate and put in a sand pit. We're only talking .22 cal. handgun with light loads.

Anyway, I was thinking about this and suddenly the light went on. Why not make an expendable screen out of a sheet of muslin painted white and put the bullet trap behind it?! Then I could play a "Dirty Harry" movie and she can shoot the bad guys! At first I thought of it more like a joke but after a while this sounded like it wasn't such a hair-brained idea after a while.

So, now I have this idea hatching in my brain and I was cogitating on it some more when I thought, "Hey! Wouldn't it be neat if the screen could detect and register bullet hits?" Now, as the movie plays, the cue detector can send a pulse to the computer when the shooting should begin and end. Then the X and Y positions of the hit could be compared to a pre-recorded script and the computer could keep score.

Now here I am, wondering if this can be done.

I was thinking that fine wires could be woven into the screen in a grid fashion so that when a projectile pierces the cloth it would break an "X-Wire" and a "Y-Wire". Good idea until the screen gets shot up. Repairing the screen would be easy. Just use white tape to patch the holes and paint over it again. The paint would act like glue to hold the fabric together. Eventually it would have to be replaced but then it would just be a sheet of muslin, available at almost any fabric store.

But then repairing the wires would be a bitch.

My next idea involves putting a video camera behind the screen to receive the light that comes through the bullet holes. The projector would put out enough light. But, then how would the machine vision software work? That would be hard.

Right now, this is still a vaporware project. We haven't even completely moved in, yet. It was just a point of discussion between us to solve our difference of opinion on the use of the room.

Which idea do you guys think? Any ideas?
 


Posted by Brad Miller (Member # 2) on 08-23-2002, 01:31 PM:
 
Whatever you do, don't run any home movies on that screen. You don't want her to get turned around during a reload and shoot the wrong target.
 
Posted by Adam Fraser (Member # 1074) on 08-23-2002, 02:14 PM:
 
Just wondering,
what do the target ranges use to register hits on their indoor ranges? It might be worth a trip to check out what they have as a set up.
 
Posted by John Pytlak (Member # 331) on 08-23-2002, 02:37 PM:
 
Links:
http://www.hernandotoday.com/news/MGAYZ0UCT2D.html
http://www.dpscs.state.md.us/pct/pstc/firearms.htm
http://www.ets-news.com/fatsinc.htm
http://www.ets-news.com/smallarms.htm
http://pollux.com/dsr97/23i-fat1.htm

Ever think about installing a Cinerama screen for your firearms practice?:
http://www.widescreenmuseum.com/widescreen/wingcr1.htm

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: +1 585 477 5325 Cell: +1 585 781 4036 Fax: +1 585 722 7243
e-mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion
 


Posted by Gerard S. Cohen (Member # 994) on 08-23-2002, 06:13 PM:
 

Probably John's links would cover these matters in detail, but you
would want to give thought to ventilation (lead dust is toxic), noise
abatement (neighbors?) and protection from ricochets in all five directions.

While working out the possibility of scoring hits on moving images,
a motorized roller screen could be set up when the location is used for showing films. You would probably want to install a motor-driven target return mechanism, so both can be wired at the same time.
 


Posted by Randy Stankey (Member # 64) on 08-23-2002, 11:45 PM:
 
Noise is not a problem. The house was insulated for sound abatement by the F.A.A due to its proximity to the runway. You could practically set a bomb off in the front yard and you wouldn't hear it inside. If no noise can get in, no noise can get out either!

Ventilation would be a factor. I'd just put in a couple of large fans to draw the air out. The guy who own the local gun shop has an indoor range. That's how he does it.

That's also where I figured out how to build a bullet trap. His is oil damped. A recirculating pump drips machine oil onto the face of the armor plates. The film creates a surface coating that "grabs" the bullets and won't let the lead splatter. His armor plates are curved into a parabolic shape (or whatever). The face downward at roughly 45 deg. The slugs hit the plates, get stuck in the oil film and literally slide down the surface where they are trapped in a sand pit on the floor.

The walls of the basement are cement block. The floor is concrete. The only part of the room that would need armor plate, besides the trap, is the ceiling. It's heavy wood sub-floor, not the wimpy plywood used in today's houses. A thinner layer of plating would suffice. The only thing needed on the walls would be some baffles to protect against ricochets. Since we would only use .22 handguns, a double layer of 1/2 inch plywood would be enough. Put them in a "/\/\/\" arrangement and that would do, I think. The only thing left to do would be to build a shooting stall... again out of double layers of plywood.

Now, all of this being said, I'm still considering a laser sight system where blanks would be used in a real gun. You would get all the realism of shooting live rounds without the problems of flying lead. The only problem would be to get a system to register hits/misses on the targets. We're back to trying to engineer a way to track shots, though.

If I could make a way for the gun to project a momentary laser spot on the screen with each shot a video camera near the projector would be able to "see" the hits. The big problem would be the machine vision system to register hits/misses.
 


Posted by Brad Miller (Member # 2) on 08-24-2002, 04:27 AM:
 
quote:
"The house was insulated for sound abatement by the F.A.A due to its proximity to the runway. You could practically set a bomb off in the front yard and you wouldn't hear it inside. If no noise can get in, no noise can get out either!"

Does this mean I get to design your home theater sound system? I promise I won't go *too* overboard.


 


Posted by Randy Stankey (Member # 64) on 08-24-2002, 11:20 PM:
 
So long as it doesn't make my ears bleed.
 




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