MM74C922N-based encoded matrix keypad

Posted on Monday, May 19th, 2014 in Arduino, hacks by DP


Raj of Embedded Lab has writen an article about his latest project, an encoded 4×4 matrix keypad using MM74C922:

In this project, we are building a simplified 16-switch keypad using the MM74C922 encoder chip, which converts a key switch closure to a 4-bit nibble output.

This entry was posted on Monday, May 19th, 2014 at 8:10 pm and is filed under Arduino, hacks. You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a response. Pinging is currently not allowed.

One Response to “MM74C922N-based encoded matrix keypad”

  1. pj says:

    This appears to be an EOL part with practically no availability from mainline distributers. It looks like you can get them on eBay, but you’re still paying $1 per chip — with all the slings and arrows that come from buying ebay parts direct from China. At that price, it is going to be cheaper to use a dedicated microcontroller. If you are already using a microcontroller, it would make a lot more sense to simply select one with enough pins to handle the keyboard.

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