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Topic: 200+ inputs and outputs: shift registers, multiplexers or other options? (Read 1 time) previous topic - next topic

james-eton

What happens when I the technique you described and press 2 (or more) buttons of the same chain? This won't work, right?
Because each button is connected to ground, if more than one button is pressed the one higher up the chain overrules any below. There is no conflict, as all resistors and buttons below are connected to ground on both ends of that part of the chain. It really is simple. In fact, I would bet most of the domestic audio and video gear with push button control uses this technique.

Jim.

PaulRB

I have made some schematics:
Oh, no, you didn't! Those are not schematics. They are "diagrams" but they don't count as schematics. Fritzing does have a schematic view. You can switch to that but you will need to do some tidying to make them presentable.

Do those '4067 breakout boards have bypass caps? If not, you will need to add them. Other than that, your circuits look ok (as far as I can tell until you can give us proper schematics).

ryanaukes

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Use Reply, then scroll down below the box and use "Attachments and other options" to attach your whatever so we see them.  The website image.ibb.co is blocked for many of us.
I changed it :)

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Do those '4067 breakout boards have bypass caps? If not, you will need to add them.
They don't have bypass capacitors I think. However, all the tutorials I have read about the 74HC4067 chips didn't use any capacitors either. How do I know what value I need and do I really need them?

Grumpy_Mike

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all the tutorials I have read about the 74HC4067 chips didn't use any capacitors either.
Then they were crap tutorials written by people who know very little about electronics.

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How do I know what value I need and do I really need them?
You always need them it is not optional, they should be 0.1uF ceramic types, other types will not work. This tells you why:- http://www.thebox.myzen.co.uk/Tutorial/De-coupling.html

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