code:  for(pos = 30; pos < 150; pos += 1)  // goes from 30 degrees to 150 degrees 

corrected code:   for(pos = 0; pos < 180; pos += 1)  // goes from 0 degrees to 180 degrees

By making the range of the servo rotation further and adding a tongue depressor to the top of the servo we provided more leverage and strength to pull the peg holding up the lid of the mousetrap.