i know why you cant blood well use it, its because u have the pins mixed up. grr i had this problem for a day when i relaised it wasnt my fault it was rapid electronics. alright ill explain it for u, from left to right the pins are like this
pin 1 (far left) = column2
pin2 = row1
pin3 = column1
pin4 = row4
pin5 = column3
pin6= row3
pin7=row2
this is confusing but its how it works. however i dunno how using a keypad will work in your system, i dont think it will work because you need 4 switches and if you have the 3 columns connected as one side of the switch and a row connected as the other side (which is what i think u are trying??) you will only have 3 switches which defeats the point of having a keypad, this system should not use a kepad by rights anyway.
this is what i think you are trying, you want the system to have a keypad wiht its column/row switches connected as switches to these 555s and the user needs to press one number (connecting the switch) then another and another for each 555 in the timelimit created by the 555s as if there was a combination that must be entered in a timelimit? tell me if i am right.
if this is indeed what you are trying then it is fundementally flawed, firstly because it would be impossible with this keypad due to the way it works, a 3 number combination lock would work but it still a poor system. u could get a 4x4 keypad with hex numbers but this is not a good way to make a combination lock system. the other problem would be that a person could just button bash and press every button between each 555 timelimit, there should be some sort of system where the user is locked out if they get it wrong (tho there doesnt have to be, mine didnt but i suggested multiple ways of doing it in my limitations, lots of extra marks). also this means that the system isnt programmable which is important for a good combination lock.
inst your coursework supposed to be in very soon tho? mine is supposed to be in on the 17th of this month. also not trying to be rude but your circuit is very simple for a combination lock, i did the same thing for mine and it was programmable and played a tune and all sorts, if you want to spice it up a bit i could help because i did the same project last year and got an A
Edit: also if u are doing the same course as me u will not learn programming but you will learn some Q basic commands which is fairly useless. for making PIC code at a starter level i would go with PICAXE because its really really really easy and take like 5 minutes to learn and 30 minutes to master and has one of the simplest programming systems ever. check out
www.picaxe.com and the software is free.