PCB DESIGN - All In One v2.5 - 32 inputs with 74HC4851

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Re: PCB DESIGN - All In One v2.5 - 32 inputs with 74HC4851

Postby gastric » Sat Nov 01, 2008 1:00 am

Synthex wrote:With this version, if you do not use USB you have to provide external 5 volts power on the USB header ;)


I thought the external power was 9V? Or is that just for the V2.7 board?
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Re: PCB DESIGN - All In One v2.5 - 32 inputs with 74HC4851

Postby Synthex » Sat Nov 01, 2008 9:45 am

gastric wrote:
Synthex wrote:With this version, if you do not use USB you have to provide external 5 volts power on the USB header ;)


I thought the external power was 9V? Or is that just for the V2.7 board?

On V2.7 board, there is a 7805 IC (a 5 volts regulator).
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Re: PCB DESIGN - All In One v2.5 - 32 inputs with 74HC4851

Postby japi » Fri Nov 14, 2008 5:02 pm

Synthex, now that the firmware handles the lcd brightness, is the 10k trimpot obsoleted? Or it has another function besides that?
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Re: PCB DESIGN - All In One v2.5 - 32 inputs with 74HC4851

Postby Synthex » Sun Nov 16, 2008 3:19 pm

japi wrote:Synthex, now that the firmware handles the lcd brightness, is the 10k trimpot obsoleted? Or it has another function besides that?

You can replace the 10k trimpot by a 100nF capacitor and a 1.5k resistor to use the firmware lcd brightness control.
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Re: PCB DESIGN - All In One v2.5 - 32 inputs with 74HC4851

Postby japi » Sun Nov 16, 2008 5:20 pm

Synthex wrote:
japi wrote:Synthex, now that the firmware handles the lcd brightness, is the 10k trimpot obsoleted? Or it has another function besides that?

You can replace the 10k trimpot by a 100nF capacitor and a 1.5k resistor to use the firmware lcd brightness control.


Good
Can you elaborate on this? that may help making this work ? :)
How's the wiring / polarity / etc

Thanks!
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Re: PCB DESIGN - All In One v2.5 - 32 inputs with 74HC4851

Postby Synthex » Sun Nov 16, 2008 6:08 pm

You must remove the trimpot.
Connect a capacitor of 100nF between 1 and 2.
Connect a resistor of 10k between 1 and 2 (optional).
Connect a resistor of 1k between 2 and 3.
You can mount this last resistor directly on the LCD display (pin 3 and pin 14).

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Re: PCB DESIGN - All In One v2.5 - 32 inputs with 74HC4851

Postby japi » Sun Nov 16, 2008 10:41 pm

Thanks a lot!
What's the result of using or not the resistor you mention as optional?
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Re: PCB DESIGN - All In One v2.5 - 32 inputs with 74HC4851

Postby Synthex » Mon Nov 17, 2008 11:17 am

japi wrote:Thanks a lot!
What's the result of using or not the resistor you mention as optional?

It's "electronically" better to use it, but it's the same result.
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Re: PCB DESIGN - All In One v2.5 - 32 inputs with 74HC4851

Postby japi » Mon Nov 17, 2008 12:05 pm

I see
Thanksssss!
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Re: PCB DESIGN - All In One v2.5 - 32 inputs with 74HC4851

Postby japi » Wed Nov 19, 2008 12:46 pm

Sorry to bother, is the schematics for this board posted anywhere? i couldn't find it, there is for the 2.7 but it has differences with this. I have a short in my 2.5 build and would be nice to have the schematics for that board
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