3.5" DX screen hacking information

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Life of Brian
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3.5" DX screen hacking information

Post by Life of Brian » Mon Sep 07, 2009 8:37 pm

You've read that it works great and is easy to use, but unless I've overlooked it there isn't a definitive "how to" guide on using the 3.5" screen with an LED backlight found on DealExtreme.com (seen here). If you're looking for a small screen that runs off of just 5v, let me recommend this one to you!

This is what the screen looks like when you remove it from its case. It's extremely thin and uncomplicated! And it looks great! Hooray! Note that the protective plastic is still on the screen in these next two pictures.
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If you flip the board over you will find an LM2576 switching regulator, meaning not only does the whole thing run off of just 5v, it's also energy efficient. This is good news if you want to, say, run an SNES and screen off of a single voltage. I'm using a TI switching regulator to run both from just four AA batteries.
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The screen is originally designed to switch between two video sources with the press of a button. I assume it's this button right here. For our purposes, just cut it off.
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This screen really is great. It's already as flat as it's going to get. The capacitors are already on their sides, with sections of the board cut out so they can lie even lower.
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And here's what you really came here for:
Red = 5v or more
Black = Ground
White/Pink = Video input #2
Yellow = Video input #1
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The only downside to this screen is that there is no audio amp or included speakers, but a quick Google search for building an LM386 audio amp will solve that problem in mere seconds.
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Re: 3.5" DX screen hacking information

Post by neverused » Mon Sep 07, 2009 10:17 pm

Do you mind if I ask what the approximate dimensions are?

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Re: 3.5" DX screen hacking information

Post by argelfraster » Mon Sep 07, 2009 11:40 pm

Awesome, I'm definitely getting one of these for a future project!
For those of you who need some guides on using the LM386 here's a good tut:
http://sci-toys.com/scitoys/scitoys/com ... ifier.html" onclick="window.open(this.href);return false;

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Re: 3.5" DX screen hacking information

Post by Life of Brian » Tue Sep 08, 2009 7:59 am

neverused wrote:Do you mind if I ask what the approximate dimensions are?
No problem. The screen is exactly 2.5" x 3", and is no more than 7/16" thick (so, just under 1/2", which is awesome). There are a few tabs on the circuit board that stick out from behind the LCD, but if you snip those off then it can easily hide behind the LCD. Look at the difference between my first and second picture to get what I mean.
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Re: 3.5" DX screen hacking information

Post by hailrazer » Tue Sep 08, 2009 4:41 pm

Also one thing to note. If I remember correctly this screen has no brightness or contrast adjustments. So if the screen is to dark or to bright.... oh well you're stuck with what ya got.
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Re: 3.5" DX screen hacking information

Post by Life of Brian » Tue Sep 08, 2009 7:54 pm

^This is true. However, the screen looks great in my opinion so... problem solved. For me, at least.
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Re: 3.5" DX screen hacking information

Post by Zeturi » Tue Sep 08, 2009 10:45 pm

I've also found this for making a 5v audio amp: http://www.epn-online.com/page/12625/5v ... r-amp.html" onclick="window.open(this.href);return false;
Looks like with these two, you can easily run most systems with 4 double a's or triple a's. If the power consumption is really low, you could get a very good amount of playtime with ordinary ni-mh packs.
If you're getting 404'd when trying to use the links in stickies, try this tutorial to find that juicy info.

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Re: 3.5" DX screen hacking information

Post by neverused » Tue Sep 08, 2009 11:46 pm

Life of Brian wrote:
neverused wrote:Do you mind if I ask what the approximate dimensions are?
No problem. The screen is exactly 2.5" x 3", and is no more than 7/16" thick (so, just under 1/2", which is awesome). There are a few tabs on the circuit board that stick out from behind the LCD, but if you snip those off then it can easily hide behind the LCD. Look at the difference between my first and second picture to get what I mean.
Thanks! I just ordered two of these.

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Re: 3.5" DX screen hacking information

Post by Life of Brian » Wed Sep 09, 2009 6:19 am

neverused wrote:Thanks! I just ordered two of these.
Awesome. I'm sure you will like them.
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Re: 3.5" DX screen hacking information

Post by Valium » Sun Sep 20, 2009 5:53 pm

I was wondering why you told me that the screen could run off of 5V. I kept looking on my 2.5" screen for the LM2576 regulator, but it turns out, the 2.5" screens on DX don't have it, so they do not run off of 5v. The lowest I've found them to work with is around 10V.

edit: this screen; http://www.dealextreme.com/details.dx/s ... r.87419775" onclick="window.open(this.href);return false;
and presumably this too
http://www.dealextreme.com/details.dx/s ... r.87419775" onclick="window.open(this.href);return false;
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Re: 3.5" DX screen hacking information

Post by 64M320N3 » Sun Sep 20, 2009 10:31 pm

This isn't a Pustom screen.
Although you probably already new that.
Sorry, not really helping here.
Making stuff with my new beautiful CNC machine!
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Re: 3.5" DX screen hacking information

Post by Life of Brian » Mon Sep 21, 2009 7:22 pm

Valium wrote:I was wondering why you told me that the screen could run off of 5V. I kept looking on my 2.5" screen for the LM2576 regulator, but it turns out, the 2.5" screens on DX don't have it, so they do not run off of 5v. The lowest I've found them to work with is around 10V.
I'm sorry, but it appears you didn't read closely enough. First of all, this guide is about the 3.5" screen found on DX, which is backlit by LEDs and can be run off of 5v.

In the guide I posted about the 2.5" screen found on DX, I posted this:
Life of Brian wrote:
XCVG wrote:Does it work at the standard old 7.4 volts everyone uses? Have you LED modded one yet?
I found a 7805 linear regulator onboard, so yes 7.4v appears to be the minimum voltage for this particular screen. It has a CCFL inside which could be swapped for LEDs of some sort, most likely surface mount LEDs.
^Above quote taken from here.

So, in what way did I mislead you?
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Re: 3.5" DX screen hacking information

Post by 64M320N3 » Mon Sep 21, 2009 8:46 pm

Oh, so I was right. :D
Making stuff with my new beautiful CNC machine!
Would you like a professional looking custom case for your portable? I may be able to help you. Check out this link:
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Re: 3.5" DX screen hacking information

Post by Valium » Sat Sep 26, 2009 8:03 am

Life of Brian wrote:
Valium wrote:I was wondering why you told me that the screen could run off of 5V. I kept looking on my 2.5" screen for the LM2576 regulator, but it turns out, the 2.5" screens on DX don't have it, so they do not run off of 5v. The lowest I've found them to work with is around 10V.
I'm sorry, but it appears you didn't read closely enough. First of all, this guide is about the 3.5" screen found on DX, which is backlit by LEDs and can be run off of 5v.

In the guide I posted about the 2.5" screen found on DX, I posted this:
Life of Brian wrote:
XCVG wrote:Does it work at the standard old 7.4 volts everyone uses? Have you LED modded one yet?
I found a 7805 linear regulator onboard, so yes 7.4v appears to be the minimum voltage for this particular screen. It has a CCFL inside which could be swapped for LEDs of some sort, most likely surface mount LEDs.
^Above quote taken from here.

So, in what way did I mislead you?
Woah jeez, settle down now.

I got mislead by the whole "Dx screen" thing. There was a link in forum 42 about the screen I bought, everyone referred to it as the Dx screen. You posted in another thread stating that you got your "Dx screen" to run on 5v. Mine didn't. Thus the confusion.

And in that other thread, about the screen that I actually do have, you say you found a 7805 regulator yet you didn't post any pictures to go along with it
Image

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Re: 3.5" DX screen hacking information

Post by Life of Brian » Sat Sep 26, 2009 9:03 am

I apologize if that came off as harsh - I intended no malice toward you, I just wanted to make sure I was being really clear.

Also, do you really need a picture of a 7805? Hasn't that been discussed enough on these forums? If you saw a 7805 on your screen's circuit board, shouldn't that be clear enough evidence that 5v won't be enough to operate your screen?
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