This is my recent design of my programmable combination lock. The input consist of 15 numbers/colours, a set, enter and reset. The input (and correct code) can vary from zero to five digits long. This leads to 813616 (=15^0+15^1+15^2+15^3+15^4+15^5) different combinations. When entering a code you do have to wait till the previous button has extended again, otherwise the previous input might get mixed up and the newly pressed input will not be recognised.

The total size of the design equals: 33W x 21L x 20H
The main redstone components are RAM, counter and comparator. The RAM consist of five times 5 bit RAM (4 bit contain the input information, from 0001 to 1111 binary and the fifth tells whether this position is being used). The counter will control which 5 bit is outputted from the RAM. The output will be inputted in the the comparator, which consist of four parallel XOR gates, from which all the outputs are linked together and will only be low when both inputs from the XOR gates are equal to each other.

There is one flaw in my design. Because when a new code is entered the RAM does not get cleared. So if a shorter code is programmed, the digits after it will remain the same and there fore an entered code will remain correct when the new correct code is entered followed by any amount of the remaining digits of the previous code. For example at the end of the video the code: "Gray Lime Cyan White Magenta" will also be correct.

I also give credit to some people of the RDF, because I saw I video of them a while back, which gave me the inspiration for the RAM and the shared wire for the indication lights. But I can not find it back.