MultiKey - One Wire Keypad

Posted on Feb 5, 2014

This project can be used for many different purposes. Probably the most used application would be to interface to any electronic project that requires a keypad. There are several ready made keypads on the market, but those work with matrix connections and require 7 pins for a 12 button pad. For new programmers, matrix keypads can be a bit tricky t

MultiKey - One Wire Keypad
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o program. My circuit can use from 4 up to 12 push buttons with only one wire connection ( plus ground pin ) making possible to use a small microcontroller like an 8 pin to use this keypad. It`s also built in a setup mode where it`s possible to change the key output rate. This setting is saved in the microcontroller`s memory. Notice that pins 11, 12, 13, 15, 16, 17 and 18 are connected to ground. For each button added just remove the ground connection and connect the pin to a push button and add the resistor the same way as the first buttons.

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