Question about sending IR codes

I'm trying to get an Arduino to send IR codes to control a stereo. I found this project:

I plan to send different series of IR codes (like a macro) in response to different button presses on the buttons I'll be connecting to the Arduino.

Are there any other circuits I should consider? Anything else I should consider?

Thanks for any help.

The circuit you reference uses an external IR transmitter IC, which cuts down on your flexibility a great deal. You should consider having the arduino do its own modulation of a simple ~36khz oscillator (from a timer output or external 555); this would give you complete control (at the expense of some significant effort) of which devices you could control. OTOH, if the dedicated IC works with your stereo, and that's all you want to control, it might be easier. Looks like there's a good set of links here:

Argh, I didn't realize that circuit isn't able to transmit any frequency.

Do you know of any circuits that would let me do this? I essentially want to make this a universal remote. I'm guessing someone must have built an arduino-based universal remote before?

For my specific purposes, I need to send 15 different frequencies, all from the same gizmo.