I have been building a Laser Tag system based on 28x-1 Picaxe over the last few months. It has now reached the stage where I was able to host a 5 player D-day landing style scenario with the system. I still plan to add features to the system in the future as this is a continually evolving project.

The guns work by generating a 38Khz PWM signal and then using this to modulate the output from the herserout pin on the Picaxe chip. This then uses a FET to drive a IR LED. On the receiving side, a 38Khz IR receiver is connected to the hersin pin. When each gun shoots it simply sends a few bytes of data containing the players ID and team number.

The system also supports the use of a LCD screen to keep the player updated about their health ammo and available clips.

A video:-

The code is too big and the forum won't let me post it here. It can be viewed here:-

Please check out my blog for more information and let me know what you think of my progress so far.


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I have been building a Laser Tag system based on 28x-1 Picaxe over the last few months.

Please check out my blog and let me know what you think of my progress so far.
Hi obroni,

Firstly, not a big issue but you have posted in the completed project area whereas your last words suggest it is still in progress? :confused:

Your send us to another website but there the scheamntic diagram link (if that is what is is) entitled Libre Tag Circuit – Rev A
at this ppage:
is broken / the pdf file is defective.

There is no reference to the project using a PICAXE chip.

Over time links to external site are/get broken and thus useless to thopse searcing here

What not post here:
1. a brief description of your project and exactly the purpose
2. Your photos,
3. Your PICAXE program code (from your earlier posts seems a PICAXE is being used)
4. your circuit diagram

We PICAXE forumites love to drool over a PIACXE project so more PICAXE related information is betteer than none


Really sorry, I started this in my lunch break at work. I meant to update it later on but got distracted. I will update my original post with your recommendations.

Also thanks for the pointer on the PDF, my PDF reader opens it fine, but I just tried Adobe and it failed. I have uploaded another version, I would be greatful if you could test this for me just to make sure.


I thought I would update this post with how the project has developed over the course of 2010.

First up is a picture of the whole project, now comprising of 8 assault rifles, 2 shotguns, a mini gun, a browning machine gun:-

The two camping lanterns you can see are used as bases in team games and also provide a method to transfer the flag in capture the flag games. They connect to the score board to update the scores:-

As well as the construction of more taggers over the year I have also been adding new features:-

CTF and Zombie modes

In capture The Flag you have to get to the other teams base and point your tagger at their beacon (camping lantern), this then transfers the flag to you and you have to transport it back to your base. In zombie mode, everyone starts off human bar one player who is a zombie. Every time a zombie kills a human the human comes back to life as a zombie. Zombies can re-spawn using their team base.

Admin Box
A small handheld box allows fully configuration of each gun and allows the referee to re-spawn, kill or reset guns.

Shot Mode
You can now select between Single, Burst or fully automatic firing

Persistent Game State
When the picaxe detects the battery voltage drop below 6v, it quickly writes all the critical game variables to eeprom.

Below is a short clip of a game that was played recently:-

The latest code is available here:-


Senior Member
Hi obroni,

This seems like a fun project..
Would it be possibe to connect multiple IR receivers to a player? As i see now, the only way to "kill" someone is shooting into their weapon? (So also making it easy to cheat by just blocking the one sensor in the gun or turning away). Adding a couple of sensors to the torso and mayby one or two on top of the helmet would increase the odds of a hit.

Mayby if each serial message had a preamble byte, you could use the picaxe's polled interrut to catch the start of the message and then use normal "serin" to catch the data?


I'm currently using 3 sensors on a hat. Each sensor has two ir receivers in it to give a wider coverage. They are all connected on the same serial bus. Your idea about having more sensors around the body is a good idea, but from testing is not needed once you are about 20-30 ft away as the ir beam spreads out like a cone. In fact once you get over a hundred ft aiming at anywhere on the torso will normally cover the head.


New Member
Well done Obroni. I can appreciate the TIME involved with all this to get to working. So much is practical experience once the idea seed it sewn.
Much cheaper than paint too.



Your project has drawn my attention, I have long considered doing something like this and have just never done it, your project has renewed interest in trying again.

I did have a few questions though.
Firstly, where did you find the 50mm lens for the LEDs, I can find them for the high power CREE/LUXON (or equivilent) LEDs but not for normal 5mm LEDs.

Secondly, what does the high/low 1 after the initial setup of the PWM do?

and finally how much of the additional circuitry in the reciever is nessescary for the 38khz reciever and how much is simply the "i've been hit" LED

Thanks, and you've done an awesome job!


Thanks, I'm glad you like what I have done.

I used the lens out of a cheap magnifying glass:-

I managed to get a bulk bag of 10 for about £12. It think the Lens you have seen for those power LED's would be the wrong type. I am guessing you have seen ones for torches that give you like a 10/20 degree beam. For laser tag you need to actually focus the beam into a tight spot.

Ah, thanks for asking about that high/low on pin 1. I have just realised that I have not updated the schematic after I added that to the code. The purpose behind it, is to switch the power to the IR LED either direct or through a 47 ohm resistor. By reducing the IR power, the guns can be used indoors without the beam reflecting off all of the surfaces.

In theory the IR receivers are all you need, however it is recommended to have the capacitor and resistor. The 2 transistors, 2 resistors and 2 LED's are for the hit lights. This gives you two team colours. In my sensors the transistors and resistors for the hit lights are only in the first sensor, the rest of the sensors hit LED's are just connected in parallel to this.


Ah ok, simple enough i suppose, how did you find the focal length of the lens, experimentation? (and what did it end up being?)

Okay, i figured it had something to do with that, i'd read what you'd said about going off frequency, makes sense it reduces power, but i was surprised that the reciever didn't complain and start producing garbage output.


Off the top of my head I think it was about 120mm, but yes I experimented with a visible light LED in a bulldog clip and moved the lens backwards and forwards. Its important to aim it at something less than 5m away and then something about 20-30m away, then pick the optimum distance for both of these.

Yes your right I use two methods for reducing the power. The resistor actually reduces the IR power where changing the frequency reduces the receivers sensitivity. They work in tandem to make indoor play possible and still be able to get 100m+ range outside when needed.

You are correct that the receivers will get garbage, but if you look at this page it explains why that isn't a problem:-

The header byte stops most noise, if the two remaining bytes don't match a "missed sound" is played. This actually adds to the realism, its like in real life if the bullets where whizzing past your ear but not actually hitting you.