Well, for my new project, i need a 12 Keys(standard 1-9,0,*,#)keypad but can't find the right size. So i am all in to make my own one. Is it possible ? i have got buttons and just need the schematics. Please help...Thankyou. Regards Sammy
lay them out in a 3 across, 4 down grid. Going across, connect the 'top' pin of the 4 rows. Going down, connect the 'bottom' pin of the 3 columns.
Then, pressing a button will connect a row to a column. Make sense?
Schematics something like this ?
Link to pic is bad.
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Sorry for that there...Thanks for the schematics anyways.:)
so, basically you just check which inputs are HIGH to guess which switch is pressed... is there any trick besides debouncing?
Dunno. A n00b myself. Sorry for that. :)
Use the keypad.h library, takes care of all that for you. I think it basically does this: The Rows are pulled high, the columns are pulled high to start. It pulls a column low, reads the rows. No lows = no key pressed. If get a low, than the row key on that column was the one pressed.
Have not looked at the code behind to see how it does debouncing, but it works very well.