Step 4: Transmitter

Picture of Transmitter
IR transmitter

You will need:
IR LED: Look for an LED with a narrow viewing angle (to ensure as much of the IR light makes it through the optics).
Higher power the better.
Pick LED’s with a wavelength that matches your IR receivers.
Get some spare LED’s as they are operated above their rated current so may burn out.

You can just attach an IR LED (with a current limiting resistor) to an output pin on the arduino and it will be able transmit, but the range of the duino tagger won’t be very impressive. In order to improve the range of the duino tagger amplification is needed.

The basic amplifier I made was a simple transistor circuit (circuit diagram provided), you may wish to consider a mosfet instead of the transistor.

Current through the LED: I aimed for about 300mA current through the IR LED. This is more than the rated current for the LED, but the LED seems to be able to cope because you are only pulsing the high current for a short time. If you are using the 5V supply from the arduino to power the LED it can only provide about 400/500mA so using 300mA for the IR transmitter Led does not leave too much for the other LED’s and speakers etc, so bare this in mind when designing building your duino tagger, it might be a good idea to add a voltage regulator capable of supplying higher currents.


You will need to use a lense to focus the IR beam, you can use the lense that came with the light gun. You can use a red LED to work out where to put the IR led to get a good focused beam.
For more details see the miles tag site.

nairdajun2 years ago
Hi guys,

I wanted to start on this project with an arduino nano and so i bought a light gun. Except this gun is rather complicated and has a recoil blowback feature. It looks extremely different to the one you have, and i dont know where to start =\. Im a total arduino noob and ive never done an arduino project before, but i was wondering whether it was possible to use the same IR firing internals without replacing the LED (because as you can see its the little silver box) as well as powering the recoil feature. From the picture you can see the wiring to the bottom, that is an actual laser pointer.
2013-03-01 11.28.38.jpg
 What model of transistor would you reccomend for the transmitter?
j44 (author)  pewepintheformats5 years ago
I used a BC337G which seems to work well. The important points are to make sure the transistor is NPN type and can cope with the high power, it should be able to handle at least 300mA. 

Hope that helps
ronmaggi5 years ago
 would a laser and reciever from an old cd player give any decent range?