I made one of these. Out of VCE. You could change the code in a instant.
EDIT: amount of numbers higher than.. like.. 7 digits turned the current variable into a "e"...
I did the same thing. I had a 'NumCount' variable that increased each key hit. After six hits, I had it divide the number so that the first number in the combo was in the ones place, then I had it round the number down, so that the remaining number was the first number in the combo, then I multiplied it to the number to have 6 digits, then it would subract that number from the original code, then add the new number.
Might see complex, but here's an example:
Entered Code: 123456
Number Hit: 7
New Code: 234567
Get it? This way if a new number was hit, no 'e+blahblahblah' crap would appear. It would just remove the first number, and add the 7th number as the 6th number. I can post the events if you like. I used alot of eye-candy. :)