Why Head Tracking?

[SEE]

Originally Posted by albx

very funny and of course dangerous... well, i took my preacautions and isolated everything... used a resistor for each led and measured the current so i don't think i will overload the usb... but always something can go wrong.

You do not need to run your LED's at max current (as often suggested in Freetrack DIY articles). I run three 1.8V IR LED's at 60% of their max current rating, wired in series and power them using a 4.5V mobile Phone Charger - max current is 70ma (0.07A) and I enjoy perfect tracking. If I were to use the USB 5V supply I would use a series resistor of around 10 ohms.