Tutorial: disable recoil in EMS TopGun II

[jasonbar]

What's different between gun #1 & gun #2?


OK, a few closeups will answer my question.


(and, no, the answer is not "One gun has a '1' on it & the other gun has a '2' on it"!)


-Jason


PS--yes, the thread subject gives it away--I didn't want to make this thread hard to find!

[jasonbar]

Rather pleased with my pair of EMS TopGun II guns (except that they don't work if the light bar's behind my tinted monitor glass...), I found that I was sometimes growing weary of the recoil feature.

It seems to hurt my accuracy a little & it gets old after a while.  Unfortunately, to turn it on or off, you need to physically disconnect part of the cable down by the USB plug, which is buried deep in my cabinet by the PC.  Not very user-friendly.

So, I wanted to make it convenient for the casual user to enable or disable recoil.

It was a pretty simple matter of putting a switch in line with one of the motor leads.


But how to package it?  After figuring out how to disassemble a gun (which was non-trivial...boy, this is a really impressive piece of packaging & engineering!) the answer was pretty clear.

Since I can upload only 8 pictures per post, this tutorial will span several posts.

Disclaimer/waiver: this describes the use of pointy & semi-dangerous hand tools & power tools.  Be careful.  If you get hurt, you can't sue me.  If you bust your guns in the process, you also can't sue me.


On to the tutorial!


-Jason

[jasonbar]

1: Remove screw cover on the chassis, just above the laser.  On one gun, I was able to rock it out partway by digging my fingernail on the key portion & then yoink it with pliers.  The second one was more tenacious, so I pried it with an X-Acto knife, using the SE/BA button as a fulcrum point.  This made minimal scarring on it.

2: Remove screw cover on grip frame by trigger guard (this is called the "magazine catch").  Unfortunately, this one is pressed in snug & flush to the part around it, so I had to dremel the heck out of it.

3: And then pry it out with a small screwdriver.  I'm going to search for a small rubber plug to cram in the hole later, but it doesn't look at all bad as it is, with this cover missing.  Go back to the 1st post.  I bet you didn't even notice it was gone!

4: Remove the left grip.  Take out 2 big slotted screws & the 2 pieces of plastic.  This reveals some small screws you need to access.

5: Remove the right grip.  Same procedure.  Actually, this step is unnecessary, but I did it anyway--at the very least, it gets these pieces away & in a safe place while you work on the gun...and it's fun to take stuff apart!

6: I was wondering how they got the recoil slide on, since it isn't split down the middle like most of the gun...it must slide on!  Getting it off is really easy.  Simply push the slide all the way back towards the hammer & then pull upward.  It should pop up easily.  If not, just pry the left & right sides apart a little--there are 2 barbs on each side that retain it in its slot--they might be catching a little.

[jasonbar]

7: Remove the 4 screws holding the laser.  Note that 2 are small & 2 are big.  Keep track!  The bigger ones are closer to the gun barrel.

8: I recommend reassembling the laser to protect it & keep its components together while working on the gun.  No need to be careful on this initial reassembly, but note that the 2 adjustment wheels' pegs go into slots in the laser housing.

9: Now the laser is safe & protected!

10: Remove the 7 screws holding the left half of the housing to the right half.  Note that 2 of these screws are flatheads.  The flatheads go in the hole on the chassis in step 1 & in the trigger guard.  Pull off the left half & set it aside (everything's attached to the right side of the gun).  I also recommend pulling out the palm switch in the grip frame at this point, as it will likely fall out sooner or later anyway.

11: Rather than drill a new hole for the recoil switch, I opted to move aside the superfluous jack that appears to do nothing.  Seems to be a headphone style jack.  I don't know what the heck it's for.  The manual doesn't mention it.

12: There's plenty of room in the grip handle, so I just popped the jack out of its cubbyhole & tucked it to the side, along with the capacitor attached to it.  This is the only part of the whole dang gun that has any extra space in it--fortunate!

[jasonbar]

13: I bought a whole lot of switches at Radio Shack & settled on this one.  Part # 275-324.  10A @ 1250VAC or 6A @ 250VAC.  Since we're running 5VDC & low current (USB can't possibly put out too much current...).  A bonus feature of this switch is the colored rubber covers.  My cabinet is black with red trim everywhere (and some orange & yellow too), so loved the red & yellow covers.

Edit: I really don't recommend this switch shortening after all--it's still causing me headaches to this day.  Just deal with the switch handle length & save yourself the hassle.

14: OPTIONAL.  To make the switch smaller & less obtrusive & look more stock & minimize accidental switching, I cut down the handle by about 1/2 its length.  WARNING!!!  The handle is hollow & has a compression spring running through it.  When you cut off the handle this short, you'll likely release that captured spring & then your switch won't work!!!  Solution: cram it back in a bit with something pointy, like a scribe, & then squoosh the handle hole back shut with pliers.  My 1st switch was well-behaved, but the 2nd one needed attention.  Deburr any rough edges, but it doesn't have to look pretty, as it will be covered later.

Substep 14.1: If you don't realize that the spring was what busted your switch, drive to Radio Shack to buy another switch, find that they're out of stock, have the clerk call the other Radio Shack in town & learn that their computer says that they have stock but they actually don't, then have the clerk call the RS in the next town over & have them hold a couple of switches for you.  Then, on the way to the other RS, take a wrong turn at a poorly marked intersection & end up on the freeway & get off at the first possible exit, which puts you pretty much at the last RS.  Then take your 2 new switches home, cut the 1st one & scratch your head about why it suddenly busted, then cut the 2nd one & watch the light bulb above your head *finally* turn on!

15: These toggle switches come with an internal washer that's keyed to a slot on the switch's threaded stud mount.  We're going to want to attach this washer to the outside of the gun & swivel it 90 degrees from its intended clocking position.  So, file that little nub on the bore.

16: Filed!  Now put it on the switch's threaded stud mount & make sure it spins freely.

17/18: Pop the power/data cable out from the bottom of the grip frame & get it out of the way.  Fit the switch in the gun & notice how it doesn't quite rest in the cavity quite right.  Pic 17 shows that the switch's stud isn't coming straight out of the bottom of the gun grip handle--it's come out at a slight angle--this will prevent the washer & nut from resting flush on the gun when assembled.  Pic 18 show that the threaded stud is floating above the gun hole instead of coaxial with it.  Pic 18 also shows the hole in the switch handle & spring inside it (see step 14).

19/20: Cover up all but the very bottom of the gun (especially the exposed gears!) & bust out the dremel & the X-Acto knives & the files & hack the case slightly until the switch pokes out to your liking.  Note that the switch is oriented such that its 2 tabs are "up"--this helps clear the wall in its cavity, and there's nothing on the mating left half of the gun that will get in the way (so no need to hack that piece).  Also note the washer with the bent tab.  I unbent the tab slightly & managed to hook it into the gap in the X/P switch (which selects between XBox mode & PS2/PS3/PC mode).  This ensures that the switch will stay stuck in P mode & that nobody will flip the wrong switch or flip this accidentally.  BONUS!  OK, pic 20 doesn't look like a great fit--the switch must've budged for this picture...

[jasonbar]

21: If you did the switch handle trimming in step 14, you'll need to also trim the rubber cover.  Since the handle is tapered & fatter on its tip, the rubber cover wil now be loose.  A little glue will hold it on (I prefer Gorrila Glue, but use only a little, as GG foams up & expands a lot when it sets!!!).  As *not* shown in Pic 21, you should put the washer & nut on before gluing on the switch cover, as it's difficult to get them on over the cover!

22: Solder a short length of wire to one switch tab.  I recommend floppy stranded wire, so you won't be fighting it as you tuck it into the gun.

23: Desolder the left gray motor lead from the ribbon cable.  Do it quickly--don't desolder the noise suppression capacitor.

24/25/26: Solder the gray motor lead to the other switch tab & solder the new short length of wire to the motor tab.


27: Time to test!!!  The gun doesn't need to be hooked up to a PC to recoil--it just needs USB power.  If you've got an iPod or other USB charger, it makes for a handy plug, if you're not near your PC.  Carefully pull the trigger a few times with the switch in each position & make sure that the toggle switch is indeed disasbling/enabling recoil.  Notice that, because the slide is removed, the normal behavior to expect here is just a moment of the motor & gears spinning.  That's normal--the slide uses a rack & pinion to turn the rotary motion into linear motion.  If the test goes well, pop the switch out, put a bit of hot glue in the switch cavity, & then replace the switch--now it will stay put while you reassemble.  The glue will not be what's holding the switch in place ultimately--the threaded stud & nut do the holding.

[jasonbar]

28: Reassembly!  Return the power/data cable to its proper notches (it's snug against the switch washer--that's OK).  Stick that palm switch back in the grip frame.  Make sure that the 2 slide switches on the PCB (for laser on/off & autofire settings) correspond to the outer switch positions on the left half of the gun body.  Now, attach the left half of the gun to the right half using 7 screws.  Remember where the 2 flathead screws go!  Make sure you don't pinch the laser wires--they should exit the slot in front of the trigger guard.  Do NOT replace the cover (as seen in step 1) & capture that frontmost chassis screw yet!  Now's a good time to rotate the outer washer until its tab hooks in the X/P slot gap & then put a *small* dab of removable Loctite threadlocker on the switch stud & secure the jam nut.  Not too tight!

29: Put the recoil compression on the shaft sticking out the front of the barrrel.  Use the slide to compress the spring, bring the slide all the way back to the hammer until it's clear of the barrel, & then just snap it down onto the barrel.

30: Reassemble the left & right grip plates.  This is 4 pieces of plastic.

31: Carefully take the laser apart & reassemble it over the 2 tabs on the trigger guard & chassis.  Make sure that the adjustment wheel posts are engaged in the laser housing slots.  After screwing it together, stick your eye right up to the laser hole on the front of the gun (make sure it's not plugged in!!!) & rotate the wheels.  You should see the laser tilt accordingly.  Now, plug the gun in & do one more test and *then* reinsert that fussy screw cover from step 1.

32: Print out a little sticker (mine is from a Brother P-Touch) to tell users what the switch does & which way is on.

33/34: Admire your handiwork, test all the buttons with the EMS TopGun II software, & play some gun games!


Epilogue: 1 more item on the to-do list for this project (I'll post when I get to this finishing touch): Find something black to cram into the hole in the magazine catch (see step 2)



Thanks,
-Jason

[mimic]

Wow, you were hard at work. Very intersting. If I get too much time, I might follow your tutorial.

[jasonbar]

Thanks--I obviously much prefer playing with hardware & hacking than setting up software--I'm great at procrastinating on software!

-Jason

[jasonbar]

I sent EMS an e-mail with a link to this thread.  It's always nice when a company responds to personal comments & such (when they're not related to buying something    ).

Here's what they wrote:


Dear Jason,
 
Thank you for your email.
 
It's a wonderful operation. It would be much more convenient with this switch.
 
That small jack is a port for the power cable for the recoil function. As that was a hole on the housing of the gun, we decided to change it to the second port for the power cable for the recoil function. Therefore, that jack is useless.
 
Thanks.
 
Regards,
Henry
EMS Production Ltd.
www.hkems.com
Tel : (852) 2748 7098
Fax : (852) 2387 9849

[mimic]

Great that you got a response from them, but let me ask you this, what would you do if all of a sudden they would start manufacturing their guns with a switch a the bottom, would you feel honored or gyped that they don't credit you/pay you some kind of royalties from you modification?

I always wanted to ask them, why won't they bundle 2 guns and 1 set of LEDs and sell it at a lower price. So many people seems to go for 2 sets and then end up with useless set of leds.

[jasonbar]

Re: gypping: I don't think that I contributed enough to expect any royalties or credit.  The profit in this product can't be all that much, so I did it for fun & education & feedback to the manufacturer.

There certainly are other creative outlets where I've been copied & not been happy about it, but that's another story...   


Re: bundle:  Darn good question--now that I've got a real live person available on e-mail, I'll ask for ya.

-Jason

[jasonbar]

Contacted HK EMS re: bundling 2 guns & 1 light bar set.  These guys are good w/ communication--I like them.

Their response:


Dear Jason,
 
I see. You are right. I consider your suggestion seriously.
 
Thanks.
 
Regards,
Henry
EMS Production Ltd.


Thanks,
-Jason

[jasonbar]

Another (unprompted!) follow-up from HK EMS:

Dear Jason,
 
By the way, most of our customers buy one gun only. Of course, for large OEM order, we could provide packges of "2 guns +1 stand".
 
Thanks.
 
Regards,
Henry
EMS Production Ltd.
www.hkems.com


-Jason

[mimic]

Of course most customers buy only one gun because there is no incentive to buy two right away. I was inquiring about buying directly from them, and if I remeber correctly there was such a small difference between buying 2 guns at once and one, that I gave up buying from them at all. Why risk buying 2 and then find out it's crap, I'll buy one and then another one later if I like it, but if the bundle would be priced nicely, I'd take a risk just for the savings. (Too late now, I already own 2)

[jasonbar]

I guess that makes me a risk-taker--I hate paying shipping twice instead of once!   

-Jason

[mimic]

I've finally decided to sit down and DO IT! I did only one gun for now and it works great, I can play now without worrying that the noise from the recoil will annoy someone. Reassembling the laser was a pain though. Thx again for great tutorial!

[jasonbar]

So glad that somebody resurrected this thread & actually found it useful!