Instructables
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This Instructable details how to make a professional-grade (waterproof) tactical pressure switch for activating rifle-mounted lasers, scopes, TacLights, scopes, etc.

I found that quite frequently I accidentally left the laser on my red dot sight turned on. This led to more than one dead battery when I needed it most. With this remote pressure switch, the dot only turns on when I need it, instead of running down before it's necessary. It also adds a professional "look" to my paintball marker, adding to the "milsim" theme.

The principle of operation is quite simple. There are two conductive pieces of copper foil that are separated by a spongy foam, and when the foil is pressed together, they connect through a hole in the middle of the foam.

I was able to make this switch and wire it into my scope in under two hours, using only materials I had on hand. Granted, had I not been documenting the process, it probably would have taken an hour or less.

Also note that the accessory can be returned to its normal operating mode by simply removing the battery isolator, shorting the switch.
 
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Step 1: Materials

Here are the parts you need:

+A scope/laser/light/etc of your choice

+An old car cell phone charger cord - If you prefer a curly cord, just like the commercial ones have, that is. Bonus points if the cable is colored black. An old telephone cable should work, too, but having a straight segment at the switch end makes life a lot easier. Also, you only need two wires to make the switch work.

+A small rectangle of plastic stock 1.5" x 0.5" - The rectangle will form the semi-rigid switch body. This can be anything from part of an old credit card to a cutout from a Chubs Wipes container. I used the latter.

+Heat shrink tubing - Black is best, as it doesn't stand out as much. You'll need at least 0.75" tubing to cover the switch itself and some smaller sizes to seal the cord end. I used a piece about 2" long and trimmed it once it was shrunk. This can be found anywhere from Fry's electronics (they have a great variety box) to Radio Shack.

+Light-duty epoxy to seal the seams between tubing segments (thanks Spork) or (in my case) super glue, if nothing else is available. Note that if you will need the switch to be completely flexible, super glue will crack, allowing moisture inside the switch.

+Copper tape - Two strips of tape form the switch contacts. I used some leftover tape from shielding my bass guitar. Aluminum could be used, except that it doesn't solder. Any conductive, solder-able tape or foil will work.

+Thin packing foam - This is what keeps the switch off when there's no pressure on it. I used a leftover sheet of pink foam, the kind that is made of very small bubbles. Whatever you use, it has to be thick enough to hold the conductive tape apart but thick enough to not need too much force to activate.

+Small strip of paper - Depending on the model of scope/sight/laser/light you're using, it might be necessary to isolate the sides of the battery from the compartment. The idea is to only have the battery connected when the switch is pressed.

+Solder of your choice
hg3414 years ago
can you give a link to the gun you use(i like the way it looks)
Patman27 (author)  hg3414 years ago
It's a Tippmann A-5, spray painted with five different shades of green and textured sand-colored paint. Just tape up the trigger area, charging handle, and the speed adjustment hole. Nearly everything else can be painted over.
hg341 Patman274 years ago
yea i have been wanting to start playing paintball for a while now and not sure where to start
Don't forget about speedballl. the matches are shorter but far more intense than any woodsball match i've ever played
Patman27 (author)  hg3414 years ago
Unless you're playing more than once a week for an extended period of time, it's not really worth it economically to buy your own gun (of course, it depends where you play and how much rentals cost). I did A LOT of research before settling on the A-5, but I'm happy with my purchase. Though I bought mine locally, the best way to get it (in my opinion) is through eBay as a package deal.

If you're into the Mil-Sim look/style of play, as well as scenario/woodsball, I would highly recommend any of the three main Tippmann markers (98C, A-5, X7). They can be pricey, though, so BT sells a nice alternative which is still insanely customizable, mind you.

Research before you buy, or you might end up sorry with your purchase. Each person might have different tastes. There's also pride in ownership, so take all gear reviews with a grain of salt.
jmanc23 years ago
A nice way to seal open heat shrink ends is to put a little hot glue in there before shrinking... You can even cut a small bit of the glue off cold and place it in there. It will melt when you heat the tubing then just squeeze it closed :o)
abadfart4 years ago
very nice i have been thinking about putting something like this on my shot gun
rhoddity4 years ago
Very cool, and waterproof no less! Haha, the third-to-last image is cracking me up (CQB anyone?). Nice marker.
r.hedgehog4 years ago
Patrick—you really ought to clean that soldering iron tip, you'll get much better performance from it. Just load it into the chuck of a drill, and then use a file or some emery cloth on it as it spins. Unless, of course, you own a lathe, in which case use that.
Patman27 (author)  r.hedgehog4 years ago
r.hedgehog,
I know what you mean. I've ground the tip down with my Dremel grinding bit, and of course, it keeps returning to this sad state. I've got a few finer tips to work with, but I figure I'll save those for working with fine electironics (i.e. adding internal bluetooth to a netbook). I've found that this tip (although pitted and battered) works quite well because the main pit holds just a bit of solder, facilitating the heat transmission to components to be soldered.
One should never, ever sand, grind, or otherwise abrasively remove the surface of the tip of a soldering iron in an attempt to clean it.

The inside of the tip is copper. Once the copper is exposed, the tip is ruined. Bare copper will quickly, as you say, "return to this sad state". Oxidized copper hates solder.

Time to buy a new tip, learn to clean it properly, and try not to leave it on overnight.

Surely there must be an instructable on cleaning and maintenance of soldering iron tips.

Patman27 (author)  SiliconFarmer4 years ago
Despite the poor condition of the tip, it's been working quite fine doing what I need. :)

As I said, I have other (non-sanded) tips, but I save those for finer jobs. I just keep this one on the iron as my general-use tip.
The most important thing is to warn others reading your instructable that sanding their soldering iron tip is not a good thing to do.

Between r.hedgehog and your comments, I could imagine hundreds if not thousands of ruined tips because people "read it on instructables" and took sandpaper to their soldering irons in a misguided attempt to clean them.

Patman27 (author)  SiliconFarmer4 years ago
In all honesty, my soldering iron tip was pretty wrecked before I resorted to grinding. It's not any worse than before. In fact, it's working better than in its pre-ground state.

I'll edit it in, though.
Hey Patman27, I appreciate your "edit that in" as you described it. The reason being just what the SiliconeFarmer alluded to, SOME people just don't read these types of things from beginning to end like one would think, and then apply the tutorial.
Most often they will pick-up a glimpse of what they want to know i.e. search on Google for cleaning solder tip, then go to the paragraph on sanding, grinding or using a dremel and the 6 watt bulb goes on over their head and they run out to the garage and grind their new tip down with the stone grinder because it had some solder on it...
This is a little off-topic but explains it well,
I belong to a fantastic site involving RC Cars, unfortunately there is a 80 - 20 mix of good and bad advice on it and even though the bad advice is "corrected" by more knowledgeable people it is done so several lines down. So kids searching power increase read: "I ran my engine really lean and gained 35% power" several lines later Joe Good Guy writes: "Hey you're going to fry your piston if you run it that lean" but all the kids seem to see is "I ran my engine really lean and gained 35% power" then 25 newbies read the same bad advice and all blow their engines and wonder why, failing to read the warning of a fried piston. I've tried to get the site owner to remove the bad advice because it causes major problems but he feels it interrupts the flow of the thread. I think your method is a decent compromise.

 ..
That applies to ironclad tips. If the tip is bare copper, make sure it's well tinned (completely coated with solder) before you use it and add a little solder after you unplug the iron. Copper tips dissolve into the solder, so even if you keep enough solder on the tip to prevent oxidation, you eventually run out of copper. Ersin makes a "Savbit" solder that is alloyed with copper, to prolong the life of copper tips, but for fine work an ironclad tip (which you clean only with a damp sponge, while it's hot) and 63/37 solder are the way to go.

That odd tin/lead ratio has the lowest melting point of all tin/lead alloys, and has the further advantage of having no "plastic range"; it freezes abruptly, with no slushy phase. If you can't find 63/37, 60/40 is more common.
Bad Maxx4 years ago
You can solder Aluminum, I've done it hundreds and hundreds of times. However it takes practice, patience, and did I mention patience? It is not fun and unless you have no other choice I would not recommend it.
That said there are several tutorials on the subject found on-line the best in M.H.O. is found here http://www.aws.org/wj/2004/02/046/
(American Welding Society)
r.hedgehog4 years ago
You're actually never supposed to bring your heat source in contact with the heat-shrink tubing. What actually works much better than a soldering iron is a lighter. Run the flame back and forth along the tubing, and it will shrink much more quickly, with less chance of melting the tubing.
Patman27 (author)  r.hedgehog4 years ago
I found that using the body of the heating element (instead of the tip) works quite well. Unfortunately, the only "lighter" I have on hand is a propane torch, and that just burns up the tubing. Running the iron _just_ over the tubing shrunk it rather quickly for me.
I've had decent shrinking results from my sister's hair dryer.
Have to agree with you! The best method I have found yet for heat-shrink tube is a hair dryer. I used to use the heat-shrink tubing several times per day, so we tried everything! Including lighters, stove top burners, heat-guns, soldering gun (worst of all tried) and even a relatively high powered laser which was fun but not recommended. (resulted in holes instead of a melt but it was humorous to watch.)
Patman27 (author)  vanmankline4 years ago
Sounds like something to try! Thanks for the tip.
Kasm2794 years ago
Nice marker!
BOOM56014 years ago
Do I see a custom paint job on that sweet A-5?
Patman27 (author)  BOOM56014 years ago
About 5 spray-paint colors, and some ferns as stencils. :)
Oh, also some "rock" textured paint, sprayed over with camouflage colors.
Nice, now make some ghillie for it!
Patman27 (author)  BOOM56014 years ago
Just remember to mask the trigger/safety/charge handle/speed adjust hole/cyclone plunger/rear iron sight!