LTTO hack

Bringing Halo style game play to Laser Tag Team Ops

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I bought a bunch of laser tag guns off ebay for cheap (the tiger electronics Laser Tag Team Ops guns from the early 2000's) to use with my church's youth group. We quickly outgrew their capabilities. So began my project to replace the guts of each gun and write my own code.

The main objective was to get custom laser tag gaming on an arduino based platform as cheap as possible. Kids would be able to play pickup games easily at our church. I wanted to add a lot of really useful features and the list just kept on getting longer and longer. 

The current feature set:

Everything runs on the Teensy 4.1 by PJRC

upgraded from 6xAA batteries to lipo battery with built in recharging

replaced monochrome screen to full color LCD st7789 screen

i2s class D amplifier for audio effects (using the stock speaker) 

added large vibration motor in the handle and small vibration motor embedded in the trigger

added visible laser 

added neopixel strips down each side of the gun and drilled out holes 

replaced navigation panel buttons with joystick and 2 tactile switches

added rfm69 packet radio for long range communication 

I'm still using the original housing/shell, the optics, the barrel tx/rx, the dome tx/rx, switches and triggers, but everything else inside the gun is scrapped. 

In addition, I'm using Circuit Playground Express boards by Adafruit as bases/respawn points. they also have rfm69 packet radios attached and they function as a node network to keep the current state of the game and aid in long range communication throughout the church

Game play is modeled after Halo. there are multiple weapon types: AR, pistol, shotgun, sniper, rocket launcher

each weapon has unique abilities:

the AR is full auto, low damage, low accuracy, high magazine size and high total ammo size, long reload time. Full auto has a side effect ability in that it is harder to get shot at while you are shooting, it acts like a shield. This is mainly because while a gun is sending out IR signals I have to ignore those signals being reflected back into the dome receiver. 

the pistol is semi auto, medium damage, medium range, and has the ability to lock on to a target and confirm a head shot single kill. This is accomplished using the rx barrel and a beacon sent out of every gun's dome much like how the original LTTO worked (but without the "warning warning" voice prompts). the pistol also has a silencer option.

the shotgun used to shoot out of the dome, but that didn't work as well as I expected, so now it shoots using the radio. This doesn't make it very shotgun-like: it's spread is 360 degrees, it shoots through walls, etc. But this ended up being really important to balance the guns because this means it can interrupt the AR's full auto, and it can increase damage the closer you get to your target. Too far away and it won't do any damage, right next to someone and it will kill them in one shot. The shotgun is also needs to be pumped for each shot and held for full reload with a long reload time. 

the sniper is also able to get headshot one-shot kills, with high damage otherwise. it is long range.

the rocket launcher is the highest damage and can actually kill groups of people. If you are hit with a rocket, or if a base is hit with a rocket, the blast will repeat and anything in the near area will get hit. At first I was using the dome to relay the hit, but I changed to sending a command via radio

Adding the radios was a game changer because I was able to get RSSI values that gave a good estimate as to how far away to player were to each other or how far a player was from any number of bases. This allowed me to implement some incredibly awesome features.

There are 10 bases throughout my church, and on the screen of the gun I've painstakingly drawn out a map of each level of the church. using the RSSI beacons from all the bases each gun is able to triangulate and estimate its position. Boom. Radar. 

I also use the RSSI values to set the range of certain weapons and to detect when you are at a certain base. The bases act as respawn points and the can hold bonus items, weapons, ammo, flags, etc. 

Health is regenerative like in Halo. That was one feature...

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This video shows the different weapon types and LED animations

MPEG-4 Video - 27.28 MB - 12/01/2021 at 15:46



This video shows what it looks like to get hit by the different weapons (shooting from a Circuit Playground Express)

MPEG-4 Video - 26.65 MB - 12/01/2021 at 15:46



Video of my first attempt at radar. The screen displays a map of the church's main level and locations of all the bases (circuit playground expresses). Blue rings are drawn with radii proportional to the RSSI signal strength. Where they overlap and add is about where I am.

MPEG-4 Video - 16.77 MB - 12/01/2021 at 15:46



remote starting a game. host gun broadcasts start to the bases, the bases send start codes every second during the count down.

MPEG-4 Video - 10.28 MB - 12/01/2021 at 15:46



Rocket explosion with coordinated LEDs

MPEG-4 Video - 4.35 MB - 12/01/2021 at 15:45


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  • 1 × teensy 4.1

  • shotgun works!

    dave.verlee03/09/2022 at 17:27 0 comments

    We play tested last night and the new shotgun works very well. It's very satisfying. It bursts 10 shots in about half a second, and each shot does 34% damage, so landing three or more will get you a one shot kill. during a few firefights I got hit, but not enough to get me fully out - which I think is the sweet spot I want it to be at. I think the burst does make it easier to aim and land a hit. I think I will be expanding this method to both the sniper and the rocket launcher since both of those prove to be more difficult to get kill shots with. 

  • fixing the shotgun

    dave.verlee03/07/2022 at 21:02 0 comments

    The shotgun ended up being way too powerful during play. I couldn't figure out a way to get more spread from the transmitting devices available. The dome LEDs weren't bright enough. a single dedicated LED wasn't bright enough. I think this is because the dome receiver has a fixed gain to make the long range barrel LED more selective. But using the radio to transmit shotgun blasts - because it goes everywhere and transmits through walls - it didn't feel like shooting a gun anymore. This method will come back in the form of some other weapon - like a gravity hammer or energy sword. 

    So I thought maybe instead of trying to create a real spread, I could simulate a spread. What if the shotgun sent out its IR message repeatedly and very quickly in one burst that would cover the span or two AR shots. That should in theory guarantee that the shotgun can interrupt an AR, and the spread of the shotgun is determined by how much your aim moves after you shoot. I can limit the effective range still by using the radio RSSI messages. On the bench it works, will test soon

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dave.verlee wrote 03/09/2022 at 17:22 point

I briefly looked into directional antennae and decided I wasn't a good enough RF engineer to do it. Though it would be really cool, I think the shape of a cardioid antenna wouldn't fit inside the gun for 915mhz. And as you said, I don't know how to switch between omni and cardioid without adding a second radio. so yea, I scrapped that idea

There is currently an overshield! I just finished the animation and got to testing it last night. works! The other pick up items are silencer for pistol, active camo, and a laser sight. I might add grenades at some point if I can figure out how to do them - they might just function the same way the rocket launcher does but with a time delay. Active camo is simple but cool - when you get tagged out all the lights on your gun turn off, and when you activate the active camo it does the same. so not only does it aid in hiding in the dark, it also makes you look "out" to others playing. 

Yes, all of the voice prompts will be there, "slayer" "killing spree" "red team has the flag" all that, plus some additional ones that I think I have to do myself, "cheating detected" "stop cheating" this is your last chance to stop cheating" "game over because you wouldn't stop cheating" 

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Hackamonth wrote 03/08/2022 at 03:17 point

First, this is awesome. Thank you for existing and doing this.

Secondly, have you considered making the radio directional? A simple PCB antenna could significantly limit your radiation pattern and reenable the use of that for the shotgun, and significantly increase the range of the sniper, if relevant. 

You'd need two antennas, that and an omni for reception (and use with the gravity hammer), but it might be a tractable problem depending on what your hardware setup is. 

Are there overshields? Other pickups? Does the original Halo guy announce the game type? "Slayer." 

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