Connecting Infrared LEDs to an Arduino

I just bought Infrared Receiver and Signal leds and I'm having some trouble connecting them up to my Arduino.

What resistance do I need to use exactly ? for both the signal and the receiver.

Time to trot out my generic led/phototransistor circuit again :slight_smile:

Connect the 'test point' to an input pin (analogue or digital depending on what you're doing with it). The switch is altogether optional. The resistor values are deliberately vague and non critical, sort of suck it and see..........