How to attach a IR led to a GPIO port?

Question

I would like to use one GPIO port to send IR signals in order to control some hifi components. Most IR codes are based on a 36kHz signal. I found an test of someone how measured the maximum speed of a GPIO port. The text is only in German but the result is, that the GPIO port has a maximum speed of about 11MHz. So it should be possible to encode the IR codes fully in software. But there is still the question how to drive the IR led.

I found an short article which describes a circuit for a 5V power supply. I am wondering if the 5V of the Rpi can be used. Does anybody know a circuit that can be used with the Rpi without damaging the device?

I need a range of about 5m. This is quite much. Is the Rpi able to power such an IR led?

Answer 1

Like the comments on you post suggest (in the links). The best way to do that is to switch a transistor which in it's turn drives the LED. That way the GPIO pins do not have to deal with the currents that might flow through the LED.

I found a nice document that explains this into great detail (but in the end it doesn't differ very much from the info already given to you). This document is written with a PIC in mind that controls the transistor, so you might need to change the value of the resistor connected to the base of the transistor.