Long distance IR transmitter


I have my arduino working to control a Lego IR receiver. Unfortunately it only works if the receiver is very close (<5 cm) to the IR diode I’m using. I just connected the IR diode to pin 13 and added a 330 Ohm resistor. I also tried with ~165 Ohm, but didn’t get a better result.

How can I make the arduino sending a a much stronger IR signal so I can control a lego car in our living room? This means it has to send an IR signal which reaches the receiver within some meters.


The lowest value I used for this resistor is 100 ohm. If the result are not satisfactory add a transistor and several ir leds in parallel. Another approach is to look for IR leds with more focus.

What code are you using? I thought that Lego used a modulated light source?

I'm using the code from the second reply here: http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1227738219

It's working if i put the IR LED very close to the arduino. So the only problem to solve is to get a bigger range.

Would something like this be a better choice: https://www.distrelec.ch/ishop/Datasheets/07520125.pdf As far as I understand I could use it like a normal LED, isn't it?

Or do I have to use something like this: https://www.distrelec.ch/ishop/Datasheets/07520125.pdf How could I get this working with an arduino?

Maybe the IR LED isn't a good spectral match

Thanks for your ideas and comments!

Can someone give me (detailed) instructions about what parts to use and how to put them together to get a wider range for the IR signal?

I'm good in programming the arduino and the PC to get the remote control working, but have only very limited knowledge in electronics.

Thanks. Hans