Parallax 27899 Keypad, Matrix Membrane, 24 VDC, 30 mA, 8-PIN, 2.7" L x 3" H

hello and welcome to easy projects so today we will take a look at keypads and how to use them with a microcontroller so you can get a ton of different ones but I just happen to have two here one that is like a screw in type you attach it from the back and a sticky type which is like a thin vinyl type but you can stick on front of something both share the same common interface though it's a an 8-pin connector and you might think how can eight pins read out sixteen switches and it's quite simple actually it's a matrix so all of these switches are combined in rows and all of these in columns so when you press the number nine for example you will combine the line from this column with the line from this row and that's how you can detect it it's only really good for pressing one button at a time although you can actually press two and read it out as long as they are in the same row or in th