How would you make a gun cam??

Have questions about a SparkFun product or board? This is the place to be.

Moderator: phalanx

Post Reply
BushWhacker
Posts: 31
Joined: Thu Jul 05, 2012 5:54 am

How would you make a gun cam??

Post by BushWhacker » Fri Apr 19, 2013 7:04 am

I have a concept for my next project, but I fear it my be a bit beyond my current abilities ... but that's never stopped me before. Fear not, what I refer to as a gun cam has no criminal or evil inclinations. What I'm picturing is a tube a 1-2 feet long with a small camera in the end -- this tube is to be mounted under the barrel of a shotgun to record video of a Skeet shooter's (a clay target sport) swing and relationship of the barrel to a thrown clay target. What I'd like to have is the ability to record the video on a Micro SD, and play it back on a PC at the range -- I have no need or desire to see the video in real time on a monitor. At first blush, this seems a fairly straight forward project.... the tube (maybe PVC), a small video camera, a power supply and a Micro SD slot.... nothing to it. Then I started looking at the cameras available here at SF, and suddenly realized I have no clue how to get video from the camera onto an SD card, much less in a format that can be played back on a PC. I have noted several comments or other posts that indicate that even if I had the programming chops, that it is unlikely a PIC MCU would have sufficient horsepower to do the processing. The fall back plan would obviously be to buy a cheap "spy pen" type of pre-built camera/DVR unit, then open it up and rearrange the guts into the PVC tube. But I'm not sure about this one either, since I've never disassembled anything and the circuits in the "pen" are bound to be very small and the connections very delicate. Not to mention that this requires moving switches, etc. and using someone else's software. Just kind of thought myself into a corner here, and since I've gotten so much gracious help on this forum before, I thought it would be a good place to come for some thoughts/advice, and a push in the right direction. Thanks Everyone.

skimask
Support Volunteer
Posts: 1244
Joined: Sun Nov 09, 2008 2:11 am
Location: Minot, N.D.

Re: How would you make a gun cam??

Post by skimask » Fri Apr 19, 2013 7:08 am

Use a cheap keyfob cam, rechargeable, microSD card built in, decent battery life, 'nuff said...
http://www.ebay.com/itm/808-3-Spy-Camer ... 255fe470b6
I ignore "one post wonders".

BushWhacker
Posts: 31
Joined: Thu Jul 05, 2012 5:54 am

Re: How would you make a gun cam??

Post by BushWhacker » Fri Apr 19, 2013 7:52 am

I appreciate that, Skimask -- your suggestion is pretty much what I think I'm going to have to do, since I don't know how to make a camera work -- and I'm sure it would be much less expensive to do it this way. But there's always the little part of me that would rather learn something new and build it from scratch, even if it costs me more to do it (the process of creating something is sometimes more important and fun than the final product.)

That being said, if I go this route - buying the keyfob cam -- is it really feasible to disassemble/reassemble the parts from such a unit?

skimask
Support Volunteer
Posts: 1244
Joined: Sun Nov 09, 2008 2:11 am
Location: Minot, N.D.

Re: How would you make a gun cam??

Post by skimask » Fri Apr 19, 2013 1:15 pm

Why disassemble it? They're small enough. Forget the tube and just mount it below the barrel.
As far as operation goes, push a button, starts recording, push a button, stops recording.
How does it work internally? Magic fairy dust. Heck, I don't know how it works either. (well, actually I do know how it works, but in this case I don't care...it just does!) And these sorts of things are the kinds of things you don't want to build from scratch anyways, especially for the price of a keyfob cam.
meh...some things, ya just gotta let the chinese make the cheap ones, buy 'em and hope for the best.
I ignore "one post wonders".

macegr
Posts: 380
Joined: Wed Feb 27, 2008 4:44 pm

Re: How would you make a gun cam??

Post by macegr » Fri Apr 19, 2013 11:56 pm

A GoPro or something seems perfect. However, your main problem will be an optical one. You'll need to figure out how to get a telescopic lens attached to this camera, otherwise the video would mostly be a useless image of an empty sky.

BushWhacker
Posts: 31
Joined: Thu Jul 05, 2012 5:54 am

Re: How would you make a gun cam??

Post by BushWhacker » Sat Apr 20, 2013 6:20 am

A really good point, macegr..... and something I hadn't considered. Obviously I'm not ready to get started yet, still got some thinking/planning to do.

waltr
Support Volunteer
Posts: 2823
Joined: Tue Sep 08, 2009 12:07 pm
Location: Philadelphia, USA

Re: How would you make a gun cam??

Post by waltr » Sat Apr 20, 2013 7:17 am

Another issue I can think of is protecting the camera/electronics from the recoil of the shotgun.

MichaelN
Support Volunteer
Posts: 1191
Joined: Fri May 08, 2009 6:14 pm
Location: Australia

Re: How would you make a gun cam??

Post by MichaelN » Sun Apr 21, 2013 7:28 pm

waltr wrote:Another issue I can think of is protecting the camera/electronics from the recoil of the shotgun.
This is likely to be your biggest problem - the acceleration can be in the order of 1000G. Having said that, small and light items will likely have less problems, as the actual forces during a shot are reduced.

fll-freak
Support Volunteer
Posts: 1518
Joined: Tue May 12, 2009 8:23 am
Location: New Hampshire, USA
Contact:

Re: How would you make a gun cam??

Post by fll-freak » Mon Apr 22, 2013 4:23 am

I work with night vision scopes for guns at work. The #1 problem is gun shock. 40 pin SMT parts will get ripped right off the board in as little at 100 shots. Connectors come apart on their own. Batteries with spring contacts break connections. You name the weird problem and we have seen it.

MichaelN
Support Volunteer
Posts: 1191
Joined: Fri May 08, 2009 6:14 pm
Location: Australia

Re: How would you make a gun cam??

Post by MichaelN » Mon Apr 22, 2013 5:52 am

fll-freak wrote:I work with night vision scopes for guns at work. The #1 problem is gun shock. 40 pin SMT parts will get ripped right off the board in as little at 100 shots. Connectors come apart on their own. Batteries with spring contacts break connections. You name the weird problem and we have seen it.
Are you able to share some of the general techniques to get around these problems? I'm also thinking of attaching electronics to firearms...

macegr
Posts: 380
Joined: Wed Feb 27, 2008 4:44 pm

Re: How would you make a gun cam??

Post by macegr » Tue Apr 23, 2013 11:47 pm

So much potting compound.

fll-freak
Support Volunteer
Posts: 1518
Joined: Tue May 12, 2009 8:23 am
Location: New Hampshire, USA
Contact:

Re: How would you make a gun cam??

Post by fll-freak » Wed Apr 24, 2013 5:24 am

Well as the software guy, I do not have great insight into the mechanical issues. I can tell you that reduction of mass on all components is important. If you have two packages for an electronic part, the lighter one is normally favored (althoug BGAs are avoided). Next the designers used CADD applications to model vibration modes and placed larger parts on nodal points where flexing is less. They also designed mounting system that again minimized flexing. One of the big problems and one I am not sure how they resolved was the breaking of gold bond wires on bare die sensors. Potting compound is just not a possibility in that it would affect the sensor and add weight above the limit. You can imagine the shock if 2 mm of gold bond wire snaps after a few dozen rounds of large caliber gun fire.
On another product, we had a terrible time with connectors. Even connectors with 5 pounds of retention force were coming apart under vibration. These were either replaced with positive lock connectors, staked with glue dots, or retainer devices added.

User avatar
Gleedaniel13
Posts: 3
Joined: Sun Jul 14, 2013 2:04 am
Contact:

Re: How would you make a gun cam??

Post by Gleedaniel13 » Wed Jul 17, 2013 8:22 am

Are you able to share some of the general techniques to get around these problems? I'm also thinking of attaching electronics to firearms...
I think you can put a watch gadget on your gun. That would be possible and just easy to make maybe.

Post Reply