I'm currently messing around with infrared LEDs and controlling my TV and various other devices from it. I have the spec and want to write a short Python script to generate these codes, and thus turn my computer/phone into a universal IR remote. I also have a receiver LED which I can use to record signals using my sound card.
I initially decided to use the GPIO pins of my Raspberry Pi and modulate them for the required amount of time, but it turns out that there's too much context switching latency to do this. I installed a LIRC kernel module which works fine, but now I want to go further.
I want to use my line out/headphone jack to drive an infrared LED. However, I'm really not very good at EE, and I don't have the tools to check the voltages. I read on another post here that the line out generates 1.something volts, and that I need to add a resistor so it has some impedance to avoid frying the sound card, but I can't figure out the values.
My LED requires 1.5 V max, but I understand I can push more if it's only for a pulse. I'll be generating the waveforms, so is there a dB level I could generate to give me adequate power to drive the LED, but not burn it? What's the voltage of my sound card at peak level?