What transistor shall I use?

I have a project where I build a Nikon camera IR remote control, similar to Nikon's commercial ML-L3 but with timelapse possibilities. It works well except that the distance between the remote control and the camera is only about 1 meter. This is when I push almost 40 mA through the IR-led. I have IR-LEDs from Kemo Electronics and according to some page on internet (not Kemo's) it can handle 100 mA. If so, the working distance may be improved.

I've understood it is possible to use transistors to amplify the current, but there is a whole jungle of them. Any ideas on its specification and what to use? I will run my Arduino Mini with a 9 volt battery.

There's a circuit for driving an IR LED on our Gadget Shield schematic (first page, bottom left).

Just about any common NPN transistor will do up to 100mA. For example, 2N2222, 2N4401, 2N3904. The resistor R14 in the schematic limits the current -- play with it until you get the current you want (it depends upon the forward voltage of your LED too).

-- The Rugged Motor Driver: two H-bridges, more power than an L298, fully protected

Oh, that wasn’t as difficult as I thought. Luckely I had BC548 (similar to 2N3904). Now I can be 4-5 meters away from the camera’s receiver.

Thank you!