It's possible to make a combination lock, but you won't have any piston doors, obviously. I'm sure there are tutorials on how to do it without pistons.
I just built a combination lock that uses three levers and a button. Search Youtube for "simple combination lock" If you go with "combination lock" you can see some pretty complicated devices, but in order to work it into a building and save a lot of space, go with the "simple" versions. And remember, just because you go through all the trouble for security doesn't mean that other people can't simply break the block your iron door is sitting on.
I just built a combination lock that uses three levers and a button. Search Youtube for "simple combination lock" If you go with "combination lock" you can see some pretty complicated devices, but in order to work it into a building and save a lot of space, go with the "simple" versions. And remember, just because you go through all the trouble for security doesn't mean that other people can't simply break the block your iron door is sitting on.
That's when you set up a second door and have lava directly above your iron door... Take THAT griefers.
Buckethead is the best guitarist ever. \m/
This thread bores me.