In this instructable, I will show you how to modify a Nerf Vulcan to automatically aim and fire at targets.  As an added bonus, this gun won't fire at anyone wearing a shirt with the instructables robot on it. I had this project in mind for a long time and finally managed to find the time to bring it to life.

If you've been browsing through my other instructables, you might have noticed that I am obsessed with Nerf guns. So far, I’ve managed to infect just about everyone around me with the Nerf virus. It is really fun to see how these plastic toys turn grown men into small boys!

My main aim was for it to look awesome; which was difficult to achieve without removing the front part of the gun. But, I managed to accomplish this without removing the barrel, and I’m really happy with how it turned out!

A big thanks goes to Bob who authored an awesome write up on how to build a sentry gun.

Please do not attempt this mod unless you are convinced that you will be able to do it; otherwise you might destroy your gun.

Step 1: Stuff you need

Stuff you need

To build the base:
  • Wood: 5 mm, 9 mm, 15 mm plywood
  • 20 x 40 x 45 mm and 20 x 40 x 128 mm rectangular block of wood (you can also use the 1.5 mm plywood)
  • Junior drum throne
  • 2 x ball-bearing (12 x 28 x 8 mm)
  • Axial ball bearing (80 x 105 x 19 mm)
  • 12 mm wooden pole
  • Wood glue
  • Sand paper
  • Wood filler
  • Paint/paint brush
  • 15 x spax/wood screws M4 x 40 mm; 4 x screws M4 x 16 mm
  • 4 x wing nuts: M5
  • 4 x machine screws: M5 x 16 mm
  • 4 x brackets
  • Two component glue

  • Servo for the turn axis: BMS-660DMG+HS
  • Servo for the tilt axis: Hitec HS-805BB
  • Wire
  • Arduino Uno
  • TIP120 transistor
  • 1N4004 diode
  • 1k resistor
  • Pin header

  • Nerf Vulcan (e.g. here)
  • 6 Volt battery pack
  • 5 kg replacement spring for the Vulcan (e.g. here)
  • Optional: Paint and plastic primer for the gun
  • 3 mm lead pearls or something similar as a counter weight
  • 6V 3700mAh battery pack
  • 9.6V 2000mAh battery pack
  • Webcam
  • Laptop 

  • Drill (3, 5, 12, 28 (to fit the bearing) mm drill bits)
  • Sander
  • Scroll saw
  • Soldering iron
  • Claw hammer
  • Phillips Head screw driver
  • Hot glue gun

Things like a scroll saw and a powerful drill are useful, but not a 100% necessary. I finished the whole tilt axis with just a fret saw and a cordless drill which was far too weak to drill the 28mm hole (I used the fret saw instead).
Can i use some other motors like geared dc motors rather than using a servo motor? Britt please help me
<p>Yes, but you will have to figure out a way for it to know in which position it is.</p>
I don't understand why is it important for the motor to know in which position it is and like you have coded such that the turret won't fire at the logo.where can we edit it so we can make it fire at desired logos
Let me correct myself, the tracking and recognition code.
Hey, I was wondering if you could possibly give me the standalone code for the logo recognition? I can't find it, and I'd like to change it to something other than an instructables logo.
Hi brittlv I'm a personal shopper and wanted to buy above for my clients kids do you sell mod nerf pieces ? Do you have an email address I can reach you on ?
<p>Hi, I am really sorry, I don't sell the parts. I have been thinking a long time to build a new version, but so far haven't gotten around to it. </p>
@BrittLiv is there any way a wireless connection could be established between the arduino microcontroller and the computer?
<p>You can try using a Wi-Fi module for the arduino.</p>
<p>*builds sentry* &quot;Sentry, goin' up!&quot;</p><p> - Engineer, Team Fortress 2.</p>
<p>what would I take out of the arduino code for controlling the gun with just the game controller.</p>
<p>Hi, lads! Me and my buddies make a cool nerf shootout video. Do you like it?</p><p>http://www.youtube.com/watch?v=jkHsyAg_3Bw</p>
<p>You don't suppose that there is a way to use a phone instead of a computer? A phone can interact with an arduino via the usb. Iv'e been googling around and have not found anything about using a phone as a sentry gun controller. (After all, who wants to use a bulky pc when they could use a phone which is way smaller, and has a built in camera?)</p>
<p>you could attempt at using raspberry pi, or banana pi for more power. If you can get the software on Linux, shoot for it, other wise you may have to install windows on it. That could easily fit in the casing.</p>
You missed my point. I asked if there was a way to use a phone instead of a pc.
<p>Here is how you control it with your phone. install processing on a raspberry pi (scruss.com/blog/2014/01/07/processing-2-1-oracle-java-raspberry-pi-serial-arduino-☺/) from there install a wireless wifi module on the pi and set up an ad-hoc network between your phone and the pi. install vnc server on the pi and a vnc viewer on your phone. run the processing script from the pi and it should be viewable on your phone after you connect to it via vnc.</p>
<p>...what does all that mean</p><p>o_O</p>
<p>yeah yeah, I see. I don't know about that, but I was giving you some extra options..</p>
<p>Im having some trouble with the wiring... can someone or @BrittLiv send me some pictures of the breadboard wiring... </p>
<p>The first image at step 10 doesn't help?</p>
<p>i cant properly see the connection. when i hooked it up it only fired.. the programs and stuff are working fine. Could you possibly email me a better pic or post one? PLease.. THANKS!</p>
did you ever figure this problem out, because I am running into the same thing! my gun is complete, the programming is functioning correctly but only firing...
<p>Could you do this with a nerf stampede? </p>
<p>Hi, I'm on step 5, just waiting for my soldering iron to get here, but I need to ask, would this still work on A linux based OS? Or is Windows required? And if I can use Linux, how would I go through doing that?</p>
Use a punisher minigun.
Hi, I am hoping you can help me here with some clarification on the trigger circuit. I have followed everything yet everytime I connect the power I end up melting part of my breadboard! Can you upload your fritzing diagram?
I tried to make a remote sniper on this basis. <br>I need a mega centurion tho.
Any other servos that are cheaper?
<p>when I run the program it says the package &quot;org.apache.commons&quot; dose not exist. might be missing a library. please help.</p>
<p>Why is there a yellow wire after the diode. I must be reading it wrong but it seems to lead to no ware nowhere.</p>
<p>Sorry. But what WATT 1k resistor did you use. The pics are to small for me to tell.</p>
<p>Hi I live in the usa and you cant buy wood in metric sizes. If I still use the Axial ball bearing (80 x 105 x 19 mm) but wood in sizes like 1/4&quot; 5/8&quot; and 3/8&quot; Will this work? I am worried the servo will sit too high or low inside the axial bearing. Thank you so much. </p>
<p>I'm considering starting this awesome instructible, but is replacing the spring a must? Would I be able to build the sentry gun while keeping the fire rate normal?</p>
<p>The stonger spring will allow the darts to fly far-er and faster, but no it is not a must. I have seen some people add a few coins and the like behind the spring so as to have the spring be more compressed. </p>
<p>i can't find m4 40mm and 16 mm screws. It might be better if the screw were m6 instead. Is it ok to replace m4s wtih m6 screws?</p>
<p>I have taken on teaching myself and completing some extremely involved and complicated projects, but this one, whew! I can't wait until I get up to speed on the electronics, then the arduino. The complexity alone isn't the only fantastic characteristic, the instructions seem extremely comprehensive. Once I am, this will be my first project. Amazing!</p>
<p>Is there another place I can get the turn axis servo or maybe a different one would work too? Is there a reason it's a digital servo?</p>
<p>Hello. Could you please give some instructions for using and installing the software?</p><p>The thing is that link you provided is not working anymore, and I am stuck on this step... everything is ready, all parts altogether...but there's a problem with this software.</p><p>Please help. Thank you.</p>
<p>Vire, were you able to get the software to work. We're about to start this project but want to make sure we don't get stuck at the end. Thanks!</p>
<p>Yes, I did got it up and running </p>
<p>Where are you stuck? It has been some time since I build it, so I hope that I am still able to help you. You can still find the page I was referring to, here: </p><p><a rel="nofollow">https://sites.google.com/site/projectsentrygun/</a></p>
<p>Hello,</p><p>I am stuck with the part where you upload the code to Arduino.</p><p>Step 10.</p><p>When I try to upload the code, it says </p><p>backup as not declared in this scope</p><p>sketch_feb07a.ino: In function 'void loop()':<br>sketch_feb07a:222: error: 'backup' was not declared in this scope<br>sketch_feb07a:227: error: 'restore' was not declared in this scope</p><p>You also have a part of the code named &quot;Backup&quot; but there's no mention where to put that piece...</p><p>Tnank you</p>
<p>Hi, I am sorry I totally missed your comment. You will have to open all three files in the Arduino software in order for it to work (hit ctrl+shift+n to open a new tab). </p>
can u make the Nerf Vulcan a CO2less paintball sniper rifle
<p>Excellent, you should make a few of these and sell them online, i'd definitely buy one. </p>
<p>Ok, so I am running this code on a 32-bit Processing, with native Raspberry Pi java libraries, and tells me &quot;NullPointerException&quot; on the &quot;camInput.start&quot; line. Nothing pops up inthe debug window, other than &quot;Successfully loaded settings from &quot;settings.txt&quot; Any help appreciated</p>
<p>Where do we place backup?</p>
Is there any where i can get one?
<p>I want to make this but the link for the spring doesn't work please answer. Thank u </p>

About This Instructable


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Bio: Hi, my name is Britt Michelsen, I'm a Chemical Engineer especially interested in Computational Fluid Dynamics. To balance all the theoretical work I like ... More »
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