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wordizlife
Joined: 08 Mar 2012 Posts: 38 Location: Canada
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Push Button Key Matrix |
Posted: Wed Apr 18, 2012 5:46 pm |
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Hey guys,
I am making a 4 button key matrix for my project. The matrix will be directly connected to 5 pins on the microcontroller. Below is a link to an image of my schematic.
http://imageshack.us/photo/my-images/195/buttonschem.png/
Is there anything any of you would suggest I watch out for? Missing diodes for example?
Thanks! |
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asmboy
Joined: 20 Nov 2007 Posts: 2128 Location: albany ny
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Posted: Wed Apr 18, 2012 6:04 pm |
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as drawn this is not a matrix
it is just 4 switches with a common
BTW: I'm always eager to learn a new trick,
but is there any reason you are using two poles to switch?? |
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wordizlife
Joined: 08 Mar 2012 Posts: 38 Location: Canada
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asmboy
Joined: 20 Nov 2007 Posts: 2128 Location: albany ny
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Posted: Wed Apr 18, 2012 6:49 pm |
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OK have it your way
Though, for at least the last 4o years or so of my professional practice,
I thought a matrix involved rows ( plural ) and columns that were interconnected ...
SO, if i were wiring a matrix of 4 switches i would use
ONLY 4 wires TOTAL.
You seem to have 5 - so i still will not call it a matrix.
Sorry but IMB, its just a garden variety 1 of 4 selector.
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Mike Walne
Joined: 19 Feb 2004 Posts: 1785 Location: Boston Spa UK
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Posted: Thu Apr 19, 2012 4:10 pm |
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OK. So you could call it a 1*4 matrix.
The general idea with a switching matrix is to reduce the number of external WIRES to a MINIMUM.
This is achieved by making the matrix as near square as possible.
In your case that's 2*2.
Mike |
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wordizlife
Joined: 08 Mar 2012 Posts: 38 Location: Canada
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Posted: Thu Apr 19, 2012 5:23 pm |
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Yes that makes sense. Thanks. So I'm guessing that there is nothing more to it then that?
As long as there is nothing that I should watch out for that could damage my PIC or give me unwanted errors I am good to go. |
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