pre-programmed chip for 9 Euros (about 9 Dollars)! It was clear that he is trying to make a profit out of it! Those people totally piss me off!
To achieve step 3, you need matrix scanning code (which is what the Keypad library is). As a bonus, the way it is written eliminates the need for the diodes in your wiring diagram, hence the simpler
Please enter a valid email to subscribe
We need to confirm your email address.
To complete the subscription, please click the link in the
email we just sent you.
Thank you for subscribing!
via Egeo 16