Arduino time base servo sweep code help Answered

Hi,
    I need help on creating arduino code for a time base sweeping servo. Specifically i would like to have my servo sweep 180 degrees and back to center every 20 minutes and repeat indefinably. Im sure its a fairly simple code but just new at coding in general

I have looked at servo sweep code sample in the arduino library but I dont know how to implement it with a timer. Hope someone can help me out.

thanks for your time

uno r3, micro servo 99