6 years, 4 months ago.

two keys pressed at the same time

Is it possible to detect two keys pressed at the same time ?

Thanks for the answer.

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1 Answer

6 years, 4 months ago.

Yes of course.

The basic way of working with these keypad is to put VCC to lines (or columns) and check values of columns (or lines) while input having pulling resistors.

When you put VCC on a line and you found VCC on a column, it means that the key at that line and column is pressed. If you continues checking others lines/columns, you can detect as many keys pressed at the same time you want.

I hope it was clear. Feel free to ask more details.

Hope it helps,


You need to change the keyboard interrupt routine. The routine returns immediately once it has found match. You need to force it to scan all the lines. Secondly, you need to returns two keys instead of one key.

posted by HM Yoong 17 Sep 2014

Oh yeah, I didn't look at the code. I only answered regarding the keypad hardware.

posted by Romain Berrada 17 Sep 2014