AT89c51 Microcontroller Password Based Lock

[krazykz]

Hello, I have to make a project using AT89c51 microcontroller with a keypad to input a passcode, then compare this passcode to the one stored in ROM of microcontroller and finally operate a lock connected with relay. Keypad is 4*3 Axis. Can someone guide me on how to interface the keypad with microcontroller and how to connect the rest of components...

 

[JaredJames]

I take it this is a school / college project and so we can't give you the answers, only guidance. It seems from your post you need a bit more than just guidance so I'm not sure how much we can assist.

Perhaps this should be in the homework help section to get a better audience.

 

[berkeman]

Hello, I have to make a project using AT89c51 microcontroller with a keypad to input a passcode, then compare this passcode to the one stored in ROM of microcontroller and finally operate a lock connected with relay. Keypad is 4*3 Axis. Can someone guide me on how to interface the keypad with microcontroller and how to connect the rest of components...

Welcome to the PF.

I've moved your thread to the Homework Help forums. As jarednjames says, we do not do your schoolwork for you. What can you tell us about how you can access the IO lines on that microcontroller (uC)? What are some ways you can scan the keypad from the uC's IO lines?

 

[╔(σ_σ)╝]

The way I would approach this problem is using an a finite state machine to model different states of the system. When you press a key your FSM should change states accordingly.

First you need to read the DATA sheet to find out that ports the keypad uses and how to enable and read from it.

Next you need to decide what kind of technique you want to use to get info from the keypad. Interrupts are a good way to do this but you can also use the polling method.

The rest should be basic assembly programming.