I am using a 38kHz IR emitter, I've taken out the IR receivers on these guns and experimented to see if I am able to transmit a signal, it's working fine, however when I connect the IR sensor back in, the hit is not registered unless it's from another gun's ir transmitter. So I believe I need to send an encoded IR signal. I tried to do a sweep of 4,8,12 digit Hex values, it might be longer hex value, and plus its a pretty unreliable strategy so far, because the IR receiver goes off at some random times, and it's hard to see if the hex values was right or maybe the lower bits of the hexvalue is what mattered and things like that. Is there another way I can go about trying to figure out what encoded signal I need to transmit with my IR emitter to register a hit on this Laser Tag gun with the IR sensor.enter image description here

The product I am working with, unfortunately I can't show you the internal circuitry of this device just yet, if its needed I can do so on my next visit to class. Other than that, here is also another helpful circuit for a basic IR emitter connected to a clock tuned to 38kHz enter image description here

Any idea on how to find the encoded signal this gun is putting out or how to send a configuration of signals to trigger a hit on this IR sensor. I have extra IR sensors and IR emitters with the same 38KhZ operating frequency to experiment with.

Also note that when I checked how the Guns emitter looked on our own sensors, it was just one pulse at a specified pulse width. So I tried to just mimic that pulse width back into the IR sensor of the gun, but that didn't also work. So I was also wondering, if it is indeed an encoded signal, then shouldnt I see a number of peaks at a time for one shot, and not just one peak of a certain Pulse width..

  • \$\begingroup\$ Hook an IR receiver up to a storage oscilloscope and look at the pattern? \$\endgroup\$ – Finbarr Feb 16 '18 at 10:29
  • \$\begingroup\$ So I should see a set of different pulse width signals if its an encoded signal? \$\endgroup\$ – fatboy815 Feb 16 '18 at 10:32
  • \$\begingroup\$ I tried that but on my ir sensor it was just one peak, I might not be sending the exact voltage peak back to the gun sensor, but I matched the Pulse Width. does the voltage peak have to be exactly the same, I think its a pretty small error. \$\endgroup\$ – fatboy815 Feb 16 '18 at 10:38
  • \$\begingroup\$ The voltage peak is likely to vary depending on the distance between transmitter and receiver. It's the pulse widths and times between pulses that identify a particular gun. \$\endgroup\$ – Finbarr Feb 16 '18 at 10:41
  • \$\begingroup\$ Alright thanks Ill take a look at it again tomorrow. \$\endgroup\$ – fatboy815 Feb 16 '18 at 10:55

It may be that you're not looking closely enough at the pulses. Unfortunately, there's no common standard for laser tag guns - every manufacturer seems to adopt their own data standards.

A simple system may just 100% modulate the 38kHz carrier with a lower frequency signal. I know of one system that uses a carrier of approximately 36kHz, 100% modulated at 1.8kHz. Without that extra signal, it's assumed to be background noise and ignored by the receiver.

A more complicated system may be transmitting actual data, perhaps with pulse width modulation of the carrier, or of the lower frequency. You might be able to deduce that, or just copy it, if you can analyse the signal well enough with a scope.


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