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this is probably a weird question that has never been asked... but I was wondering how/if it is even possible to decrease the range of a infrared emitter?

here is why I need to know:

I am playing around with making laser tag weapons and I was working on a shotgun. how I have always seen shotguns is they do more damage the closer you are! so I am trying to decrease the range of the infrared led. is that even possible?

If you guys have any ideas please let me know! I'm new to using infrared emitters so I was hoping y'all could help me out :)

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    \$\begingroup\$ You should be thinking of how to either reduce the light transmitted (reduce the drive current) or reduce the sensitivity of the receivers (filters or change the gain of the input amplifier). You have provided no links to datasheets and no circuit schematic so how can we help further? Please capitalise properly to be taken seriously. \$\endgroup\$
    – Transistor
    Jul 13, 2017 at 20:54
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    \$\begingroup\$ VTC - Way too little information provided to be able to consider this as a legitimate design question. \$\endgroup\$ Jul 13, 2017 at 20:57
  • \$\begingroup\$ I felt like I've seen this question before.... like perhaps yesterday or the day before. \$\endgroup\$
    – user103380
    Jul 13, 2017 at 21:01
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    \$\begingroup\$ You could make your emitter emit in a wide cone (which will give you another analogy to the shotgun) \$\endgroup\$
    – The Photon
    Jul 13, 2017 at 21:08
  • \$\begingroup\$ A piece of wax paper will diffuse the IR emitter output pretty well. It's surprisingly good, actually. Getting the threshold right for your receivers will be a matter of experience, though. Just try it and see where it takes you, then adjust either with more wax paper layers or else by adjusting emitter current or both. \$\endgroup\$
    – jonk
    Jul 13, 2017 at 21:33

2 Answers 2

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As someone who has played around with laser tag weapons, there are some easy options.

The better, as a permanent approach, is simply to increase the resistance of the current limiting resistor that should already be in series with the emitter (or add a second resistor). LEDs will glow even down to very small currents, so try different resistors until you find one that gives the range you want.

A shotgun may be best with a bare, un-lensed, emitter. Longer range guns normally have lenses on the front to focus the beam.

A quick fix, for instance to cut the power when playing indoors, is to place opaque card in front of the LED with only a small hole in it.

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  • \$\begingroup\$ that's dude! this helped a lot! \$\endgroup\$
    – Max
    Jul 15, 2017 at 4:03
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Add a lens or other means to cause the beam to spread over distance.

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  • \$\begingroup\$ That would mean that the user wouldn't have to be as accurate. \$\endgroup\$
    – Transistor
    Jul 13, 2017 at 22:08

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