I'm planning a laser tag project. It will have suits with guns.
This is a technical question. I don't have a code yet, and I have nothing prepared except for ideas and sketches.
I want to be able to detect a shot in a field on the player's suit, on their chest, and on their upper back. It should be around 20cm * 15cm. My question is, what technology should I use?
I thought about using lasers and a field with photoresistors, but their angle is too low, and only lucky shots will reach phototransistors. Well, I can fill that field with a lot of phototransistors but that's inefficient. I also thought about using IR, but its distance is very short. I tried looking for ways to improve it, using lens, for example. I didn't find anything.
The standard technology for laser tags is IR LED with limited range.
Advantages:
Cheap
Eyesafety is less an issue due to the divergency of the diodes
The divergency also solves the problem of the required density of sensors at the target
Disadvantage: Low range
Laser diodes and high sensitive detectors are used in professional systems for military training equipment such as MILES or AGDUS (US and German laser based training systems, just Google for those keywords).
Advantages:
Range of up to 4000 m possible (vehicle target equipment), 1200 to 1600 m for individual target equipment
Not only hit/near miss but also data transfer like shooter ID, ammo type, etc. in the laser data protocol
Disadvantages:
Very expensive compared to laser tag
Complex detector electronics required (high sensitivity while coping with day/sunlight illumination)
High tech optical beam forming required to establish a divergency that widens a laser source to a beam of about 40 to 60 cm at small range up to the maximum range.
Expensive and complex eyesafety calculations and proof by external accredited lab: Lasers are more dangerous, in minimum for the eyes, if not designed carefully (which includes the work of specialists in physics and optics, this is quite often dramatically underestimated!)
In a nutshell: For non-professionals the use of IR LEDs is the only safe solution. Otherwise you risk to harm yourself and others, not talking about the technical problems and skills involved...~
Technical information (though from 1981 still valid regarding the challenging physics ):
Just to add: Professional systems are based on pulse laser, except one that used continous wave laser (CW), the latter never reaching the ranges as it was based on reflection from cloth to detector to reduce density of detectors.
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