LightArms - A Budget Laser Tag System

A relatively simple, inexpensive laser tag system with customizable game modes

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Laser tag systems with sensor vests and multiple game modes are typically very expensive. Since I like digital electronics projects, and I have much more time on my hands than money, I decided to design and build a laser tag system with multiple game modes that I can afford to build.

This project was somewhat influenced by the LZRTag project, but is very different and should cost *much* less to build.

The general design is to have each player have a gun, connected to a vest, with a "mother beacon" to setup the game and report players' scores.


  • uses a single Vishay TSOP4838 IR receiver as main component, with a PNP transistor to buffer the signal
  • uses 2 RGB LEDs as hit indicators
  • casing: TBD (probably mostly 3D printed)
  • all sensors are connected via a 6P ribbon cable (1.27mm pitch) with 3x2 2.54mm IDC connectors
  • component cost: <$1 per sensor (from LCSC)

Gun "Magnum":

  • runs directly from 2x AA batteries
  • input: trigger, team select, 2x weapon select (backward and forward)
  • 3D printed casing
  • uses STM32F0 (STM32F042C6T6) microcontroller
  • uses Vishay TSOP4838 IR receiver (same as on sensor) for hit detection as well as communication with mother beacon
  • uses IR333-A (R) IR LED with lens for shooting as well as communication with mother beacon
  • uses generic red laser diode for laser dot
  • uses 8-Ohm speaker for audio output (used to indicate when hit and when game begins and ends)
  • uses standard SPI flash memory module to store sound data
  • no display
  • component cost: ~$4 per gun (from LCSC)

Current status:


  • Genesis (first gun design; basic pistol): design is mostly complete, but abandoned because its sound doesn't work, and it's awkward to assemble anyway
  • Magnum (basic pistol; very similar to Genesis): electrical design is complete; firmware is playable but still needs work; initial physical design produced, but needs redesign

Mother Beacon: PCB designed; casing design still in concept stage

Vest: sensor PCB designed; needs some modification to the casing design and some sort of vest to be attached to

If anyone wants to contribute, please message me! I would greatly appreciate it.

KiCad files (and LCSC BOM) for the Magnum gun PCB

Zip Archive - 587.08 kB - 07/06/2020 at 13:06


(OBSOLETE) KiCad files for the first gun PCB (codenamed "Genesis")

Zip Archive - 177.56 kB - 04/09/2020 at 02:32


KiCad files for the sensor PCB

Zip Archive - 35.06 kB - 04/06/2020 at 04:07


  • Status Update #6

    Ben Larson01/28/2021 at 06:50 0 comments

    It's been a while, but I have a lot to report on:

    First off, the Magnum gun worked, but wasn't durable enough to survive some playtesting. Because of that, along with some of the parts no longer being easily available, and my ambition to add improvements, I have designed a new gun, named "Broadside". It has fixes and new features, and uses screws for assembly rather than plastic welding with a 3D printing pen. While the total price of construction has basically doubled (as far as I can tell, considering that I'm using some components from the old gun for the new one, and ordered different quantities of different parts), it has some big new hardware features, namely WiFi and an LCD screen. Please note that neither of these are required for core functionality, so both can be left out for a cheaper version of the gun with fewer features, and I intend to make sure the firmware supports guns with or without these components. Also, the new gun design uses generic, easily-acquired parts when reasonable. Everything should be easy to find on LCSC, Aliexpress, and Banggood. I'll add links at some point, likely after I've more fully verified the design. I expect I'll eventually even get around to writing some assembly directions.

    As I think I've already said, feel free to message me if you want to build my guns. With COVID-19 restrictions, I have more time than motivation anyway. (Remember it was supposed to be 2 weeks to flatten the curve?)

  • Status Update #5

    Ben Larson07/06/2020 at 13:38 0 comments

    I've nearly finished the Magnum gun now, and the price comes out to ~$40 for all the internal components to build 10 guns. The sound is usable (but very low quality), and the physical design is essentially complete. The code still needs some more work, but it's able to test all the hardware, which is what I need right now. I have one fully assembled gun, and I'll have more that I can complete as soon as I get the right switches and some better 3D-printed gun casings. My current 3D printer prints PLA fine, but needs a lot of help to print PETG reasonably well. PLA isn't heat-resistant enough to survive in a hot car, so I don't want to use that, but PETG should handle it fine. Anyway, I've ordered a Creality CR-10 3D printer, which should be able to print PETG very nicely, so I'm waiting for that.

    The first Mother Beacon PCB design is complete and ready to be ordered and tested. I'll probably be ordering it today, along with enough components to finish my 4 partially-complete guns and to build 10 more guns after that.

    I still haven't solved the vest problem, but I've ordered some vests to see whether I can find one that will work. Once I get a good vest, I'll attach sensors to it, verify that the setup works, then order more vests and more sensor PCBs and components.

    Overall, I'm pleased with the progress I've made, and I'm looking forward to finishing this project.

  • Status Update #4

    Ben Larson05/25/2020 at 20:47 0 comments

    I was able to get the IR communication all working, so now I'm really close to having basic laser tag functionality. It turned out that my big problem was that I had fried the infrared receiver I was trying to use, and once I replaced that, I was quickly able to get it to work.

    As for the sound, I've tried writing a simple program to emulate the I2S-like LSBJ protocol used by the PT8211 DAC, but I still can't get any sound except for a whine from the electrical noise. At this point, I've basically given up on audio for the Genesis gun, and I'll use an MCU with I2S support for the Magnum gun.

  • Status Update #3

    Ben Larson05/23/2020 at 23:19 0 comments

    Well, my PT8211 DAC chips finally arrived, so I've started testing the sound system. Unfortunately, the I2S protocol used to communicate with the DAC is more awkward to implement than I thought, so right now the only sound I'm getting is from electrical noise. The PWM signal used to drive the LEDs creates a fair amount of noise, so I should probably decrease the amplification on the Magnum board. I just wish I knew how much to decrease it by.

    On the firing side, I have gotten the gun to output a 38kHz IR signal, which I can detect using an IR receiver and an oscilloscope. I haven't been able to detect the signal yet from the MCU, but that seems to be a configuration issue. The STM32 timers are incredibly powerful, but also rather confusing.

    If anyone reading this happens to be familiar with implementing I2S using SPI or using input capture on an STM32 MCU, please message me.

  • Status Update #2

    Ben Larson05/11/2020 at 19:51 0 comments

    The boards and most of the components for the "Genesis" gun have arrived. I've tested what I easily can, with some eventual success. I got the soldering wrong multiple times, which resulted in a lot of frustration. Now, I've been able to confirm that at least some of the hardware works, but I haven't gotten the chips necessary for testing the gun's audio system, which is what I've been least confident about anyway.

    My gun casing design is close to working, but it's a lot more awkward to assemble than I expected. In particular, the buttons aren't on the PCB, so I'm connecting them with wires, which is a pain. With that, along with other issues, I'm inclined to verify the sound system, then work on the "Magnum" gun design. I've lost most of my patience for gluing in buttons and switches, so I'll try to design my new gun to have everything except the trigger and the speaker on the PCB. I need 2 guns to adequately test the IR optics, so I'm really hoping everything goes well. Fortunately, I can remove the lens and/or replace the resistor for the IR LED if I get too much ricochet. I'm confident that my IR signal won't be too weak, at least indoors.

    For the "Magnum" gun, I need to upgrade my 3D printer to use a dual extruder, so I can make the supports more easily removable.

    I have less energy and free time than I used to, and my mental health is pretty bad, so I won't be moving this project forward all that quickly during the next few months, but I'm not just putting this project on the shelf and leaving it there either.

  • Status Update #1

    Ben Larson04/22/2020 at 03:12 0 comments

    The sensor and "Genesis" gun PCBs and components have been ordered and will eventually arrive sometime, probably early May.

    The casing design for the "Genesis" gun is partially complete, to the point that I need some of the components to figure out proper dimensions so everything can fit together nicely.

    I've written most of the low-level code for the firmware, but I need the actual hardware to test it. Who knows how many bugs there will be?

    I've started on the "mother beacon" (does anyone have a better name for it?) PCB design, which incorporates several parts of the gun PCB design, so I'll want to verify those parts work well before getting too far. Fortunately, I shouldn't have much trouble getting one of the guns to function as a very basic "mother beacon" until I have the proper PCB and code.

    I haven't really designed the sensor casing yet, so I'll be working on that soon probably.

View all 6 project logs

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gordon wrote 04/09/2020 at 01:06 point

built a small proof of concept just for myself a while back, 2 units total. most info learnt from: might wanna check that out. 

  Are you sure? yes | no

Ben Larson wrote 04/09/2020 at 02:54 point

Cool! It seems like everyone else is using various types of radio communication, while I'm doing everything with IR.

Can you tell me how much current your IR LED used in your setup? And did you use any lenses? I want to have a better idea of how much power is actually needed, and whether I'll be able to use diffused sensor casings in my system, or whether I'll need to stick with clear like everyone else.

  Are you sure? yes | no

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