unactivated tripwires [closed]

I have an tripwire enderman farm as shown here:

At initial setup, the tripwires did activate(with the click sound) and I also did check that the tripwires did extend the pistons but after awhile, the tripwires suddenly deactivates and when I test it out, the pistons does not extend.

My tripwire enderman farm is very similar to the one in this video:

Any ideas?

EDIT: Oh, too bad this question is closed. Short follow up: the trip wires will work a lot better if the on the sandstone floor. Maybe because it is a totally even flooring.

EDIT2: Since from the previous edit, I felt guilty for not sticking to my problem initially so I changed half a layer of my design back to tripwires and this is the result:

It works a lot better with no blocks under the trip wire hooks as Kevin Reid suggested.

EDIT3: Moved all the edits below the question and also.

In my conclusion, from what I can see tripwires works the best when there is either a block under every tripwires and tripwire hooks or no blocks at all under each of the tripwire components.

2 Answers

It looks like your tripwire hooks at the far end are over solid blocks. There are known glitches in this case. For fully reliable behavior, make sure that the tripwire hooks at both ends are over empty space just as the tripwire itself is.

(I'm not at all sure this is the entire problem, but it can't hurt to fix this.)

Your tripwire hooks appear to not be extended. I am guessing that you lost a string at some point. In fact I think your design may be flawed. If something is directly below a piece of string it attaches to the floor. If there is air below the string it floats. I suspect when the pistons extend the string is going from being attached to the air to being attached to the piston. Then the piston retracts and the string completely drops.