Real Laser Arm Cannon From Metroid!




About: Engineer/Maker/Hobbiest

There aren't many video game characters quite as awesome as Samus. Universe saving bounty hunter with one of the coolest weapons in all of sciFi. When I saw Instructables was hosting a Video Game based competition, I immediately knew it was her weapon I wanted to make a reality.

And this is the result! This laser cannon is powerful enough to easily destroy a balloon instantly, ignite flammable materials on contact, and even cut through thin plastic! Not to mention it is easily visible in air (by a camera, dont look at it). It even has light and sound effects!


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Lasers of this power are incredibly dangerous. Without adequate protection this laser WILL blind you with a reflection. That being said, devices like this can be safe, far safer than many open frame laser cutters, if the proper steps are take.

FIRST: Always wear eye protection built for this laser. This can not be overstated enough. Good safety glasses mean the difference between a laser you have to be careful around and a laser you couldn't pay me to be in the same room of.

SECOND: Have PLENTY of extra laser glasses around. You're going to want to demo this. NEVER demo without everyone around you having laser glasses. There are some fairly inexpensive bulk packs out there.

THIRD: Have full control over the space you demo. This means no one entering without your permission. No opening doors, and no uncovered windows.

FOURTH: I have built in a unplug-able port for the laser. Whenever the laser isn't about to be used, unplug it. This is a final safety so no one who is not supposed to use it hurts themselves or others.

Essentially, treat the laser as what it is. Understand the danger and avoid it. If you follow these steps the laser can reach the point where it is "usable" and "safe enough". But never treat it like a joke. Finally, this is intended as a demonstration. If you replicate this project, learn the dangers on your own. I am not responsible if you hurt yourself.

Step 2: Components:

For this project you will need the following:


  • 3D Printer (Or Print Service like This)
  • Soldering Iron
  • Laser Safety Glasses!!

Step 3: 3D Printing and Design!

The most difficult part of this project was definitely the 3D modeling and design. The way I designed this cannon started with a few reference images I found online. I approximated the scale by comparing the size of my forearm to Samus's, then primarily used the "Curve" tool along side typical model making skills to design the basic shape. I split the arm into 9 main pieces in order to facilitate easier printing.

I then went through the process of adding the custom details. This includes a core mount which holds the laser, battery, speaker, circuit board, and toggle switch. I also cut out channels along the sides to add additional NeoPixel strips, and a flat plate in order to mount the custom NeoPixel ring.

In order to secure the pieces together I went with my go-to method: 3D printed threads. This allows for a strong, concentric method of attachment of two 3d printed pieces without having to mess with any extra hardware or glue.

All the pieces were printed on my QIDI Tech One printer at .3mm resolution at maximum speed. I removed support from around the threads, however that's not typically necessary unless you were attempting a higher resolution. I've found at higher resolutions support can sometimes gum up the threads and make them a little too tight. I've included my print profiles in the drive link for anyone who is curious.

I'm a strong believer in sharing editable versions of files so I have provided both the STL and editable Solidworks files both here and on my thingiverse page.

Step 4: Electronics!

The circuit I designed for this project has four main sections:


At the top of the circuit there is a irf9540n P-Channel MOSFET connected between a 5 volt regulator and the power from the battery. The reason I use this is because the switch I would prefer to use has three states. To one side and the middle it locks into place while on the far side it acts as a momentary switch. I close to use the momentary switch side to act as a digital input to the arduino to "charge the laser", for the middle to be "powered" (but not doing anything), and for the far right to be "turned off". The best way I could think to do this would be to connect power to the center lead of the switch and run the far right lead to the base of a P-channel MOSFET. That way, when the switch is connected power is to the right, power is applied to the MOSFET's base and the circuit is disabled. When the switch is to the far left, the voltage goes through a voltage divider and then to an Arduino pin where the signal can be read. When the switch is in the middle, no voltage is applied, and the pull down resistor on the P-Channel MOSFET closes the P-Channel MOSFET and allows the Arduino to be powered.

Laser Driver:

The 2.5 watt laser diode is driven by a TIP31A NPN transistor. I had to cut off the heat-sink of the transistor when I found the clearance was just a little too tight. Though I wouldn't recommend this, it should be fine. The transistor is driven by a 1k ohm resistor connected between pin 7 and the transistor's gate. I also have a blue LED and resistor in parallel with the laser diode to act as an indicator for whether the laser was intended to fire, even if the laser isn't plugged in. This is a far safer method of trouble shooting.

Audio Driver:

In order to enable basic audio sound effects a small, 2n2222 transistor and accompanying 48 ohm resistor are used to act as a basic audio driver. A 8 ohm speaker is connected between 5v and this transistor, which is connected to ground. The Arduino oscillates pin 11 on and off rapidly, causing the speaker to oscillate back and forth and generate sound.


For the few who haven't worked with them before, NeoPixels are a strip of individually addressable RGB LEDs. Essentially you apply power, ground, and give it a data signal and you can control a huge line of them. There are 8 sections throughout the cannon built to house NeoPixel Strips and one for a custom NeoPixel ring. Simply wire them together in one long chain, and connect one end to pin 9 on the Arduino.

Step 5: Assembly Part One: the Core

After the electronics are done, the next step is the mechanical assembly. We start by assembling the component I've termed the "Core" based around the 3D printed "Core Frame". This is the entire functional part of the cannon, minus the NeoPixel strips. The cannon will function with only this component assembled, everything else is simply ascetic.

  1. Begin by securing the toggle switch into its designated hole using its included nut. Have the non-momentary side facing outwards.
  2. Next secure the 2.5 watt laser module using two M4 7.5mm long machine screws. I had to use two washers for mine as my screws were too long, however that shouldn't be a problem for you if you have the correct size.
  3. After the laser is secure screw in the electronics board using the two M2 self taping screws. These should bite into the plastic to hold the board in place.
  4. Using super glue and insta-set spray attach the battery and the speaker to the sides of the Core Frame. Alternatively you can use velcro or hot glue.
  5. Plug the battery, switch, laser, and speaker into their designated ports.

At this point the Core should be ready to test! Throw on a pair of safety glasses and fire it up! You may have to adjust the focus of the laser in order to get the best results.

Step 6: Assembly Part Two: Lights!

Now its time to add the lights! If you look at the models i made you will find that at the end of each channel and the middle of each ring there are rectangular holes. These are intended for the power and data wires for the various NeoPixel strips to be fed through. I found the best method for me was to jump from the electronics board straight to the lowest point and work up from there.

  1. Start by threading together the bottom most pieces, ensuring the pattern lines up.
  2. Add servo extensions to your "input" and "output" for the bottom half of the cannon. I chose to attach these to the lower end of the strips towards the outside of the cannon.
  3. Cut and super glue each LED strip into its channel.
  4. Add wire connections between "close" LED strips. Thread on a new ring after each soldered set of wires.
  5. Add one long PWM wire from the bottom set of LED strips and the rings.
  6. Add a long PWM wire to the custom NeoPixel ring, it should be the end of the chain.. Do not glue down the NeoPixel ring.

*Note: I forgot to put a hole in the bottom most ring channel. This forced me to tap into the side channels, which left a slight gap and some unusual wiring. I have since updated the model, meaning you shouldn't have to worry about that.

Step 7: Assembly Part Three: Finishing Up!

Now its time for the final assembly!

  1. Start by screwing the bottom two pieces and the "Core frame" together as far as they will go.
  2. Plug in the "input" 3 wire connector from the bottom half into the connection on the electronics board. This is the start of the NeoPixel chain.
  3. Solder the "output" 3 wire connector from the bottom half into the NeoPixel strip on the core frame.
  4. Glue the custom NeoPixel ring into place.
  5. Thread on the second to top 3D printed piece.
  6. Plug the output from the top ring NeoPixel strip into the custom NeoPixel Ring.
  7. Thread on the very top 3D printed piece.
  8. Snap in the two side pieces at the base of the cannon. You can glue these, but they are designed to be a friction fit.

Step 8: Code!

Now its time to upload the code!

The following is a basic description of how the code works. The code begins by waiting in a while loop until the toggle switch is pressed. It then moves into another while loop until the toggle switch is no longer pressed. This is the "charging" mode. In this while loop a variable is decremented over time, until it reaches 10, while at the same time playing a sound effect and animation. This variable controls the frequency of the charging sound effect and the speed of the NeoPixel animations . It also is used to control the length of the laser pulse once the toggle switch is released, thus allowing you to make a more "powerful" laser shot by charging for longer.

Step 9: Done!

And that's it! All it takes to build a functional laser cannon from the video game Metroid! Great if your particular corner of the universe is under assault from black balloons. As you can see from the video this laser is easily able to pop balloons, my favorite demonstration. It can also light matches, gun powder, burn paper, or even punch through thin plexiglass. Being a 2.5 watt laser, its very powerful as far as homemade laser weapons go.

I hope you enjoyed this project! If you have any suggestions for how I could improve it, I encourage you to leave them in the description.

Stay Awesome!


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37 Discussions


Question 10 months ago

Do you have separate files for pieces 3 and 4 for people who don't have a multicolored 3d printer?

1 answer

Question 1 year ago on Step 4

sorry to bother again you but 2.5k, 2x5k,or 25k also do the values need to be exact or is there a margin of error
also what are parts U1 and U2s names so i can find them

1 answer

Question 1 year ago

can I build this without the high power laser and replace it with a a ring light to flash instead or is it required because I love metroid and this would be awesome to build.
Also if this change is made do i still need a lipo or would a 9 volt work to supply sufficient power

1 answer

Answer 1 year ago

Yeah a flash light would work fine, as long as it could handle the voltage from your battery. Yeah any battery between like 8 and 12 volts would work no problem.


Question 1 year ago on Introduction

Hi. I like this project but there are a couple issues. First, the photos of the componants (mostly the resisters) on the completed circuit board do not match the schematic. I built it using the schematic. Is that the most accurate plan? I have not tried it yet. Second, I tried to download the code but all I got was a page with a bunch of 3D renderings but no code. Please advise. Thanks

1 answer

Answer 1 year ago

The resistor values varied slightly just based on what I had on hand. None are crucial values (only ratios to each other) so the schematic is slightly more optimal.

In terms of code, what do you mean the code isn't there? Inside the folder there are a bunch of 3d models and a folder labeled "samus_gun_code". Its at the very top of the page. Let me know if you can't access it for some reason. Heres a specific link to it:


Question 1 year ago on Step 8

Great project. I am half completed on the 3D printing. Electro-mechanical prototyping is my strong suit so this really caught my eye. Coding however is my weakness so I have to ask.... do the 26 lines of code printed in the Instructable represent the total program or do you have a separate , more complete ".ino" file. The "upload the code" link took me to the .stl and mechanical files but no sign of a code file. thanks again for the great work.

1 answer

Answer 1 year ago

Weird. I could have sworn I uploaded it. It is there now. And yes, the code in the screenshot is just an outline.

Awesome! Make sure youre careful ;p


1 year ago on Step 9

I am very inept when it comes to coding and electronics. The fact you show step by step so i can understand how to use it/how it works is inspiring.


1 year ago

You mentioned SolidWorks. Is this the software you used or something that will Save As a SolidWorks file. I used to have access to SW when I was engineering. Now retired and wishing I had a copy, just can't afford the annual license. Beautiful project by the way. ~KB7GP Dave~

2 replies

1 year ago

Don't! Just don't.

Take it from someone who has a cute little squiggle burned in his right retina from a fixed mount lower power laser contained in a small laser engraver. Yeah, I'm an idiot for forgetting my glasses. It reflected off of something I was engraving.

And YOU! You demonstrated this with a Chrome plated office chair behind the balloon! Even a small reflection from this is going to cause major damage to someone's sight.

As far as understanding the danger, you just gave a step by step on how to build it. Now you don't really need to understand the danger do you? You can just build it even if you're 10. And I know many people under the age of 25 who would be more worried about impressing their friends before worrying about the actual danger.

So is this supposed to be used in an isolated non-reflective room with no windows in it? Are you supposed to supply everyone watching your demonstrations with laser safety glasses? You certainly can never take this out in public and use it. I highly recommend switching to an extremely low power laser pointer and stop this nonsense.

The actual weapon design is impressive and looks cool, but there are some things you just shouldn't build even if you can.

3 replies

Reply 1 year ago

Ok. So the number of comments talking about the danger caused me to add an extra entire step discussing the danger. Check that step and see if theres anything I should add. That being said, just being there are people out there who will ignore warning doesn't mean people with true skill should be bared from sharing what they know.

And yes actually. Thats what I do. I bough an 6 pack of pretty good quality laser glasses for like $120. Only problem is they work so well I can barely see the laser dot. Its well known that its a myth that a low power laser reflection can cause vision damage through laser glasses. It can't.

And yes. You should only demo in a space you control, with no uncovered windows, and everyone wearing saftey glasses.


Reply 1 year ago

Very well written warning. I applaud you for taking the time to write it and taking heed of the warnings.

p.s. The quip about the "open frame laser engravers" made me lol. Yes. One moment of my stupidity. Clicked START then put on the glasses. Instead of putting on the glasses then clicking START. And I know the dangers. I know better.

I was lucky. The damage looks like it does having a small curly hair in your vision like a spec of dust. I only notice it when looking at screens with a white background.

Thanks again for the warning.


Reply 1 year ago

Haha of course. Sometimes I forget how easy it is to ignore a small disclaimer. Its important to be exceptionally clear with something like this.

Thats actually kind of ironic. The reason I had the laser diode for this proejct in the first place is I am building a laser engraver. Before I made any other decisions about its design I knew I was making it shrouded, with a switch on the "door". Its far to easy to just hit "go" and not think about it.


This is super cool! Thanks for sharing.

I am curious, is this laser enough to incapacitate a housefly instantaneously?

1 reply

Reply 1 year ago

Uncertain! I think it is. However I wouldn't really try it. Lasers like this are pretty dangerous.