roboman's Content

#170697 New Semi-auto Gun Idea

Posted by roboman on 19 August 2008 - 05:38 PM in Homemades

(Also posted on NerfX)

I just had this idea for a simple semi/full auto gun. The mechanism is very similar to one used by a person on spudfiles, and uses many of the same ideas as Captain Slug's Arr and ABP5K on nerfhaven. Basically, it consists of a short PVC tube w/ an endcap on one side. There is a hose barb mounted in the endcap, which goes to the trigger valve. A piston with a sliding o-ring mechanism is connected to a piece of 1/2 inch brass which slides over a piece of 15/32 inch brass that is connected firmly to the endcap's inside face. The 1/2 inch brass slides inside of the barrel (17/32" or 9/16" brass) and doubles as the bolt. A spring holds the piston in an open position. When air is allowed into the tube, the piston goes forward, stripping a dart out of the magazine, until it slides off of the 15/32" brass and air is allowed into the bolt. The air is channeled behind the dart, shooting it out of the barrel. When the trigger valve is closed, the return spring pushes back the piston, causing the o-ring to uncover the vent hole and allow unused air to escape. The gun will have a selector switch to choose between semi/full auto, and the valve will be activated by a solenoid. The solenoid will be triggered by either a 555 timer circuit configured as a monostable multivibrator or another 555 circuit configured as an astable multivibrator. Both circuits are adjustable by independent trimpots for precise ROFs. The trigger will be a simple snap-action switch that activates the oscillators. The trigger itself is a basic pushbutton valve that opens when pushed, and closes when released. A small LPA tank will be the stock, and will be able to be charged by a small double-acting pump. The solenoid will use two 9v batteries in parallel, to allow longer run times before a battery change is necessary. The rifle will be configured as a bullpup, and will have a 10-round removable box magazine in front of the stock that is expandable to a larger drum magazine.

Does anyone forsee any problems?

(Yes, I know that I forgot to show the oscillators, and they go in between the snap-action switch and the solenoid, with a DPDT slide switch for a selector.)

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Yes, I am new to this forum, and I am only 13, but I can be an asset to this board if you guys give me a chance.

#170699 I Really Need Help Here,

Posted by roboman on 19 August 2008 - 05:46 PM in General Nerf

Just drill the head off of the stripped screw with a regular drill bit. I did that on a NF once, and it worked perfectly.

#170703 Barrel Splitters?

Posted by roboman on 19 August 2008 - 06:03 PM in Homemades

If you want multiple barrels, go to Home Depot or Lowes, pick up some PVC and Tees, and use that for your manifold.

#170747 Runescape

Posted by roboman on 19 August 2008 - 08:38 PM in Off Topic

I play, but its pretty boring.

#170750 Air Pressure Gun

Posted by roboman on 19 August 2008 - 08:40 PM in Homemades

Is the 1/2 PVC supposed to move?

#170762 Cpvc Outside Diameter

Posted by roboman on 19 August 2008 - 09:20 PM in Modifications

Mine is 1/2 SCH40.

SCH 40 PVC isn't CPVC.

#170777 Other Projects

Posted by roboman on 19 August 2008 - 10:00 PM in Off Topic

I build robots.

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This one, Trilo-BOT, won 3rd place at Robogames in San Francisco.

#170943 New Semi-auto Gun Idea

Posted by roboman on 20 August 2008 - 01:52 PM in Homemades

That, or the air pressure will just compress the spring and release it all in one shot..

The oscillating solenoid valve should prevent that.

#170944 Recon

Posted by roboman on 20 August 2008 - 01:53 PM in General Nerf

They have a tendency to chew up darts.

#171004 New Semi-auto Gun Idea

Posted by roboman on 20 August 2008 - 05:43 PM in Homemades

More complicated than it really needs to be. You can accomplish the same effect using only pneumatic components.
It would be more reliable to have the breech actuation speed controlled by a flow regulator.
And have the trigger valve(s) setup to simply empty the breech actuator into the barrel while closing off the supply line from the tank.

Unfortunately, I don't have the money/access to the tools for the construction of a full pneumatic system. Also, I am much more comfortable working with electronics.

#171265 New Semi-auto Gun Idea

Posted by roboman on 21 August 2008 - 01:55 PM in Homemades

Your system is actually more automatic than semi-automatic, but you don't have enough control over the timing of each part of the feed and firing cycle to be able to adjust the setup to increase reliability.

There are potentiometers on each of the circuits, which control the frequency of oscillation of the valve. A monostable multivibrator only pulses once for a set amount of time each time the input pin is pulled high (or low). An astable multivibrator oscillates continuously while the input pin is high (or low).

See below diagrams:

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An astable multivibrator; R2 is swapped with a potentiometer, and the other component values are altered to achieve the desired frequency.

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A monostable multivibrator; the resistor is swapped with a potentiometer, etc.

#171756 Modification and Paintjob Pictures

Posted by roboman on 23 August 2008 - 11:59 AM in Modifications

Basic NF AR removal.

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Its airbrushed with Testor's paints.

EDIT: Picture resized.

#171983 Vulcan With Roto Track Spring?

Posted by roboman on 24 August 2008 - 09:14 AM in Modifications

this may be because i've only moded my scout

If you've only modded your Scout, then it probably isn't a good idea to jump in and mod your Vulcan.

I was hopeing to increase some range because im only getting some were around 15'' (eye balled it so it may be more or less) with stock.

15" doesn't sound right for a Vulcan. Mine gets around 35 ft right out of the box!

#172291 New Semi-auto Gun Idea

Posted by roboman on 25 August 2008 - 10:42 AM in Homemades

Sorry for the DP, but I have made a change to the gun's firing mechanism, after realising that the original mech. was too inefficient (thanks CS). Instead of two separate 555 oscillators controlling the solenoid valve, I will end up using a Parallax Basic Stamp 2 microcontroller. Also, instead of the original breech actuator, I will implement an electromechanical actuator to close a simple breech, which has compressed air run straight through it.

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#172295 New Semi-auto Gun Idea

Posted by roboman on 25 August 2008 - 11:05 AM in Homemades

Do you plan on actually making this? If so, when do you plan on having it done? Pneumatics are not my thing, and do not interest me all that much, so I don't have much to add on that point.

Yes, I do plan on making this, but it may be a while until its finished, since school is starting up again.

#172335 New Semi-auto Gun Idea

Posted by roboman on 25 August 2008 - 01:35 PM in Homemades

That would work, but I prefer working with microcontrollers, and that's way outside of my abilities, construction wise. My revised design should have a relatively high flow rate, and should be fairly simple to build.

#172884 Paintball Tanks With Nerf

Posted by roboman on 27 August 2008 - 03:42 PM in Homemades

[indent=1]Ok, I have a question, my mom just bought an electric pump, it works on bikes, as well as cars...there is a gauge to show how much PSI is currently in the object it's pumping with about a 250PSI maximum, it was bought for $30. It is charged via eletric outlet and there is about a 2' hose that comes out of the front.

Is that an Air Man pump?

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#172886 Modding My Nite Finder And I Have A Quick Question

Posted by roboman on 27 August 2008 - 03:51 PM in Modifications

Solder the red wire from the switch to the positive terminal of the mini-mag, and solder the black wire directly to the ground terminal. If the mini-mag has an internal resistor, cut off the existing one inthe gun (the little brown cylinder w/ metal caps), and wire that tab to the positive battery terminal.

#173230 E-tape On Plunger Head

Posted by roboman on 28 August 2008 - 05:39 PM in General Nerf

Use silicone lube.

THAT'S WHAT SHE SAID!

added that hilarious quote to my signature, while playing with my butthole.

#175057 Labeled Vulcan Internals + Faq

Posted by roboman on 04 September 2008 - 09:31 PM in Modifications

How do I get that stupid hatch off of the gun itself?

EDIT: Never mind, I figured it out.

#180931 Pen Pump

Posted by roboman on 01 October 2008 - 09:28 PM in Homemades

That is a nice design, and it looks pretty easy to build, but of course, you could have gone to the store, spent $5 or less, and bought a decent ball pump that is the same size, and is more efficient.

#180937 Could I Make This Shoot Nerf?

Posted by roboman on 01 October 2008 - 09:38 PM in Homemades

It looks a lot like the classic Bow n' Arrow put out by Nerf a long time ago. It probably won't work very well without a lot of work done to the plunger, but hey, you never know.

#180942 The Official Snapbow Writeup

Posted by roboman on 01 October 2008 - 09:49 PM in Homemades

I used the #62 spring in my SNAPs, and a 5 year old could prime it (not kidding!). Unless your brother is weaker than a kindergartener, I think he'll be able to cock it.

#180951 Other Projects

Posted by roboman on 01 October 2008 - 10:09 PM in Off Topic

This year for Halloween, I am building several fright props for my front yard. My favorite of these is called Trash Can Trauma (TCT). It is basically a head jumping out of a trash can, attached to a 12" pneumatic cylinder.

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A normal looking trash can...

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The guts.

12" stroke!

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Solenoid valve.

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Power switch.

It's not quite done yet, and I am going to add a monster mask on top of the rod.

#180955 Nerf In Space

Posted by roboman on 01 October 2008 - 10:14 PM in Off Topic

You could also build a spacesuit for the guns, so they wouldn't blow up. I agree, space nerfing would be fun, but terribly impractical and costly.

#180957 "stix" Commercial

Posted by roboman on 01 October 2008 - 10:24 PM in Off Topic

A company (not really a company, but just some random dickhead in Texas who has never made or sold a product) calling itself Anascape claims patents on analog stick and rumble technology (along with many other technologies used in game controllers) used in the Wii Gamecube controller, Wavebird, and Classic Controller. This little shit company sued Nintendo, and won. Now they are calling for a ban of nintendo's GC and Classic controllers, and Nintendo is trying to postpone or avoid that. Wii-Motes, however, are in no danger at all, and Analscope (as I will now refer to them) has no valid patent claims on Wii-mote technology (though it tried).

How can you claim a patent on analog stick technology? It's used in almost every modern R/C transmitter and game controller!

#181057 Newb Needs Some Schoolin - Arm-brace Mounted Blaster

Posted by roboman on 02 October 2008 - 06:14 PM in Homemades

Would a regulator like this be sufficient? Overkill?
http://www.hustlepai...p/11530101.html

That would work, but this would be cheaper.

#181429 What Is A Silencer? And A Breach Idea.

Posted by roboman on 04 October 2008 - 08:55 AM in Modifications

In an actual silencer, there is a baffle to slow down the escaping gases from the gun. This would make it impractical for nerf guns, since the pneumatics are almost silent, and it wouldn't do much to a springer. There is a silencer design in the "homemades" directory by Zero. This may help. However, we aren't dealing with noise in the first place, so it probably would be just for aesthetic appeal. You really don't need a silencer for anything other than an air cannon, unless you have huge amounts of air exiting your barrel at a very high speed.

EDIT: You might want to fix your spelling and grammar before the mods get here.

#181577 Pressure Bladder Now, Gun Later

Posted by roboman on 04 October 2008 - 08:08 PM in Homemades

I wouldn't use hot glue, if I were you. That stuff can barely hold any pressure at all, and it looks really ugly.

#182851 Helical Clip Gun

Posted by roboman on 10 October 2008 - 06:09 PM in Homemades

You would need a lathe and a milling machine to pull a helical clip off, unless you just happen to have access to an injection-molding machine or a rapid prototyper. If you mave any of the above tools, hten by all means, go for it! I for one want to see how it turns out. If you don't, however, forget it.

#183323 Automated Foam Cutter - New Pics/vid

Posted by roboman on 12 October 2008 - 06:08 PM in Darts and Barrels

You should use one of these for your control system. I've been using them for a few years now, and they are really easy to program, and have 16 I/O pins. Also, you could use servos as your actuators.

#184027 Nerf Gun Science Projects

Posted by roboman on 15 October 2008 - 09:43 PM in Modifications

Dude, I wouldn't do anything that involves weapons in your science fair project, especially if it means showing pictures of you holding a nerf gun, or God forbid, actually have your model include a nerf gun! Seriously, if your school is anything like mine, they'll think that you're planning the next Columbine. I would do something about the aerodynamics of stock darts (think wind tunnel testing), but that's just me.

#184035 Vulcan Safety Removal

Posted by roboman on 15 October 2008 - 10:03 PM in Modifications

Dude, don't tape it down. That tape will never hold. It only takes a couple of minutes to clip the wires off of the switch, twist them together, and solder them. Then, you can tape the wires to the inside of the shell so they don't get caught in the mech.

#192015 Rapid Fire Rifle

Posted by roboman on 25 November 2008 - 11:44 PM in Modifications

I seem to remember tube magazines having being mentioned before and deemed as impractical. Maybe if you had used the very handy search engine first you would have found this.

#194186 Not A Rifled Barrel

Posted by roboman on 05 December 2008 - 10:20 PM in Homemades

If you really cared about spin stabilization, you could just add a tail at the end of the dart (sort of like a Nerf football). I have made little "fletchette" dart, using a toothpick with fins and a noseweight housed in a break-away FBR jacket. However, the fletchettes can embed themselves in corrugated cardboard when shot from a lightly modded NF, and are pretty dangerous for wars, due to their sharp tips.

#194189 Why Hasn't Somebody Thought Of This Before?

Posted by roboman on 05 December 2008 - 10:29 PM in Homemades

I don't mean to hijack the thread, but since the Big Salvo was mentioned from the start, I'd like to know if there is any significant body of work here on NH on the topic of piston type homemade valves. Like the valves used in SSPB, TS, Hornet, BigSalvo, SMDTG, etc., etc.

I'd really appreciate a few links or even suggestions what to search for, rather than to divert this thread away from sleeved-pin valves. I too was unable to solve the sleeve sealing problem in a way suitable for regular folks to make copies. But I still hope someone can.

By the way, I did build one where the sleeve was eliminated by using a solenoid to pull the valve open. Really cool, very effective, and at that time, the parts could easily be bought mail-order. Anyone who likes spending $50 and carrying around six D-cells (e.g., a Vulcan) might like my idea ... yeah, exactly my conclusion -- maybe for spudguns, but not practical for nerf.

I think this might be what you're looking for. The inline valve could probably be built for $20-30, and it would have a much better flow rate than a QEV. I think there was a thread on spudfiles about making an inline piston valve from an empty deodorant can. While that may be a little big for nerf guns, it could certainly be scaled down to the size you need.

#194819 Bsa

Posted by roboman on 08 December 2008 - 07:17 PM in Off Topic

I'm first class, but I only need a few merit badges to advance.

What troops are represented here? I'm in T126 (Long Beach, CA).

#200845 Mega Maverick Shoots 100'

Posted by roboman on 03 January 2009 - 03:29 PM in Modifications

You should consider using stefans. They're cheaper than stock darts, and if you make them well, they will go farther than stock darts.

For the timing to work out, the valve shouldn't trigger until the end of the trigger stroke. That's when the turret is aligned with the valve.

Nice mod, though!

#202180 Maverick Mod Gone Wrong?

Posted by roboman on 09 January 2009 - 09:21 PM in General Nerf

Pictures would help...

#202181 Springs Help

Posted by roboman on 09 January 2009 - 09:23 PM in Modifications

Try a hardware store (I'm not sure if they have ACE hardware stores in Canada), but any hardware store should have springs.

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