Tutorials/Combination locks

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Combination locks are a type of redstone circuit. They generally have a number of components which must be set in the right combination in order to activate something such as a door. Combination locks can be very useful in creating adventure maps. Note that if you are playing in survival multiplayer, other players will still be able to break into the mechanism and cause it to activate without knowing the password.

Order-insensitive combination locks[edit]

Lever lock[edit]

Lever lock
16 (2^4) combinations

A lever lock is one of the easiest redstone locks to create. Each lever doubles the number of combinations the lock has. The possibilities can be found using 2 ^ n, where n is the number of levers used.

When constructing, you will probably first want to place the levers and put them into the desired positions. Next, you should place the redstone torches and repeaters. Torches go behind levers that are down and repeaters go behind levers that are up. When you are done, all of the torches and repeaters should be turned off. If not, double check any components that are turned on.

Item frame lock[edit]

Item frame combination lock
512 (8^3) combinations

Item frame combination locks are a step up in complexity from lever locks. Items in item frames can be rotated into 8 different positions. This rotation can be detected by a comparator which will output a signal strength from 1 to 8 depending on the position. Since each item frame has 8 possible states, the number of possible combinations can be found with 8 ^ n, where n is the number of item frames.

If you want to make it extra tricky, it is also possible to detect an empty item frame by when a comparator doesn't output anything. Simply omit the redstone torch and leave a repeater connected to the comparator.