A close-up view of the trigger. A metal rod with a string attached is hooked under the angled rebar. The corn is piled around the trigger and the hogs eventually will disturb the metal rod, causing the door to fall shut.

if you fix the anglebar with one pointing foward and one pointing backaward , then when the hog roots the corn it will trip from either way.they don't have to be hitting it from behind.just a though,thats the way I fix mine.