12 Button Keypad $2.50
tonyp12
Posts: 1,951
http://www.goldmine-elec-products.com/prodinfo.asp?number=G18422
I was able to follow the traces and came up with the circuit in the attached file.
Needs 7 prop pins
With 3-out-8 mux/serial IC etc. you could get down to 4 pins.
* or # could be separated from columns/row if you want it to be multi press with other buttons.
Getting it down to 4 pins just using pins in tri-states, that is nice challenge.
I was able to follow the traces and came up with the circuit in the attached file.
Needs 7 prop pins
With 3-out-8 mux/serial IC etc. you could get down to 4 pins.
* or # could be separated from columns/row if you want it to be multi press with other buttons.
Getting it down to 4 pins just using pins in tri-states, that is nice challenge.
555 x 1000 - 190K
Comments
I've used these in a couple of projects. Twice the price of your find but you do get four more buttons.
Duane