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Welcome to KTag🔗

KTag is laser tag with nothing locked down. Every circuit board, every line of firmware, every 3D-printed part, and every byte sent over the air is open for you to build, study, change, and share. No subscriptions, no apps doing who-knows-what with your data, no broken toys you have to throw away because you can't fix them: just blasters you made yourself and a game that's yours to shape.

KTag started in the summer of 2016 as a project for a dad and his kids. It was intended to take a weekend or two. It did not. Instead it grew into a complete system: several generations of blasters, a shared game engine, a wireless protocol, and an assortment of Android apps. All of it is free for anyone who wants to join in.

There are three ways to have fun with KTag. Most people start with one, and end up doing all three.

Play🔗

Two KTag players battling

KTag is laser tag, first and foremost. Pick teams and go. Blasters are configured wirelessly, so there's no need to fiddle with menus before the game. A phone or tablet can join the battlefield too, but you don't need a phone to play.

Make it your own, too. Load custom sound packs onto a plain USB stick, and dress up your blaster with animated NeoPixel light effects. If you've ever wanted your blaster to sound more like science fiction, or less like science fiction, or speak to you in Latin, well, now you can.

Build🔗

Soldering a KTag circuit board

A KTag blaster is something you make, not something that comes from the store. The current design, the 2024A "32ESPecial", is an ESP32-based main board in a body of PVC plumbing pipe and a few 3D-printed parts. Along the way you'll solder, print, cut, and assemble, and at the end you'll have a blaster you can explain (and repair!) down to the last resistor.

The complete design files, bills of materials, printable parts, and step-by-step assembly instructions are all here. If you'd rather not hunt down the hard(er)-to-find components yourself, you can get a 32ESPecial Blaster Kit.

Code🔗

Writing code for KTag

Under the hood, every KTag device runs SystemK, a portable game engine built around a finite-state machine. Blasters, phones, and gadgets talk to each other using documented IR and Bluetooth® Low Energy protocols, so anything that speaks one or the other can join the game. There's also wide compatibility with existing laser tag systems.

Want a new game mode? A different way to score? A device nobody's thought of yet? The firmware, the Android apps, and the protocol specs are all in the KTag git repos, ready for you to fork. Or you can ask the community, and let them go to work on your behalf.

Open All The Way Down🔗

KTag is licensed so that it stays open, for you and for everyone after you:

What License
Software AGPL-3.0-or-later
Hardware CERN-OHL-S-2.0
Documentation CC BY-NC-SA 4.0

Get Started🔗