Interrupts

I am somewhat new to the Arduino, so hopefully I’m not biting off more than I can chew here. I think I am going to need to use interrupts in my source code that I’m working on. Are they hard to do? I looked at the tutorial on them in the dedicated ‘tutorial’ section of Arduino.cc, and it looks pretty discouraging…I need to have a robot that ‘wakes up’ from sleep (low power mode) after receiving sensory input. Is this possible? :-/

I haven’t done it myself but I don’t think it is difficult. Have you seen this tutorial: http://www.arduino.cc/playground/Learning/ArduinoSleepCode