Blast doors

I made a remake of an old video on how to make a door with pistons using Redpower (to be specific, you need logic gates, wiring and covering plates). It can also be used to make other contraptions with the same idea (a hidden access), as I used it to make other videos. The pointers to make this kind of stuff are:

• A repeater connected to an AND gate gives you power after some time (0.4 seconds with a vanilla repeater at max delay), but will lose the power inmediately.
• A repeater connected to an OR gate gives you power inmediately, but takes some time to lose that power (again, 0.4 seconds with vanilla repeaters).
• A piston (or a sticky piston) cannot move a powered (or extended) piston, but can move an unpowered one.

Here you can see my previous video, and the other two with the same basis: