We've built a DIY-Lasertag system - Here are some images (too big for attachments):http://imgur.com/TMoFSLEhttp://imgur.com/pIKQw17http://imgur.com/N9HHR1E
It does work: shots and hits are registered, with corresponding beeps.
But we've run into a fundamental problem.
For the system to work outside, the LED signals need to be rather strong.
But if that configuration is used inside, reflections can be strong enough to trigger a hit.
Basically you can shoot the ceiling and hit everyone in the room.
To give you some technical details:
The system uses a Vishay TSAL 6200 with a resistor as IR emitter.
On the receiving side there are 5 TSOP 4838 (38khz) in parallel.
The problem seems unsolvable. As soon as we decrease the strength of the signal, the system becomes unusable outside.
But if we keep the signal strong, the reflections are problematic.
We tried optimizing the message protocol: Different number of bits transmitted, different lengths for marks and spaces, etc.
Nothing seemed to work.
Then we set up a test-station. One of the weapons connected to a notebook, over serial. To display the received message.
Behind the weapon was a sheet of cardboard.
A direct hit on the receivers and a reflected signal from the cardboard was virtually identical.
We believe that this can't be solved in software.
But experiments in hardware are expensive.
And we don't really have the know-how to make an educated guess about how to solve the problem.
I took a look at your sensor domes.
There is a number of differences:
1. 3 sensors to each dome
3. 10uF capacitor.
We have 5 sensors, but they are wrapped around the head. I think that at most two sensors can be hit at once.
We use 38khz sensors.
We do have capacitors.
Is this a potential fix?
How many sensors are usually hit in your systems ?
Is the 56khz frequency important ?
And we tested our optical system.
The lens is a Google cardboard lens: 25mm diameter and 40mm focal length.
This is glued into a PVC pipe optics system.
We optimized this to have a spread of about 10cm per meter.
In a 10m distance, the cone will have a diameter of about 1m.
Is this a sensible value ?
Maybe outdoor lasertag systems need to be much more focused.