Opens only if you jump over the lower tripwire and trigger the upper one
Works very well against creatures and moderately well against other players.
On this screenshot you can see the circuit triggered by the two hooks on the inner side of the wall; these forward the signal to a comparator, which then forwards when only the upper signal is active.
Behind the entrance is another tripwire, which closes the door behind you again.
Good idea, but I'm not a fan of unnecessary pistons like in this case. You could have built a RS-NOR latch, for example from this one Variant B.
Of course you can build it that way ^^
Hmm, I forgot about RS-NOR-Latch...
xD I also always use huge parts like pistons or something, currently mostly funnels.
Great idea, actually safe.
Good idea to build a hiding place
Levers can only be operated by players. I've been looking for a very long time for a version where only I can get in.