2 pushbuttons on JW24MOD-A8-16

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DeeMoNay
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Joined: Sun Dec 05, 2010 5:11 pm

2 pushbuttons on JW24MOD-A8-16

Post by DeeMoNay »

Hi,

So I have these tiny circuits and I want to connect only two pushbuttons to one of them. Am I allowed to wire one pushbutton from Y0 to X0 and the second from Y1 to X1? Would I need a diode on each pushbutton? If so, would I connect the cathode side to X or Y? Then, if I can do this, can I connect two more push buttons to Y2, Y3, X2, X3 in the same fashion?

I ask this question for the reason that I was supposed to order the JW24MOD-A8-8 and made a mistake on one of them. Your assistance is always appreciated and I am most impressed with this effective and diminutive device.

Derek

EDIT - I read on the datasheet that the cathodes have to connect to the Y lines. I also did a bit of experimentation and have answered my question. It is possible to connect only two pushbuttons to this device. This is the second time in as many days. I'll leave the post here for anyone who may want to read it. Great board and I applaud your efforts.
Guido Körber
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Re: 2 pushbuttons on JW24MOD-A8-16

Post by Guido Körber »

Never mind about the diodes. If there are less than 3 buttons there is no chance to get a phantom key, and even then it happens only if you have a certain configuration of buttons.
DeeMoNay
Posts: 27
Joined: Sun Dec 05, 2010 5:11 pm

Re: 2 pushbuttons on JW24MOD-A8-16

Post by DeeMoNay »

Guido Körber wrote:Never mind about the diodes. If there are less than 3 buttons there is no chance to get a phantom key, and even then it happens only if you have a certain configuration of buttons.
So then do I need to use the diodes if there is no risk of simultaneous key presses? I am currently using diodes, but would prefer not to if they weren't needed for my particular application. I would like to just to do the matrix sans diodes if it's "legal".

Thank you,

d
Guido Körber
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Re: 2 pushbuttons on JW24MOD-A8-16

Post by Guido Körber »

Yes, you can leave out the diodes if you don't have combinations of three or more keys pressed simultaneously. And even then it is only a problem if the three keys form three corners of a rectangle in the matrix, in that case the third corner will appear to be pressed too.
DeeMoNay
Posts: 27
Joined: Sun Dec 05, 2010 5:11 pm

Re: 2 pushbuttons on JW24MOD-A8-16

Post by DeeMoNay »

Guido Körber wrote:Yes, you can leave out the diodes if you don't have combinations of three or more keys pressed simultaneously. And even then it is only a problem if the three keys form three corners of a rectangle in the matrix, in that case the third corner will appear to be pressed too.
This is GREAT news! Although I like to sit and solder diode after diode, I am pleased I can stop. (this is a joke, btw...i really don't like to solder hundreds of diodes)

Derek
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