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Project Help and Ideas » Touchscreen LCD

July 27, 2009
by mmontalvo
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Has anyone tried modifying an LCD touchscreen from a palm? I was wondering where to get the information on how to interface with it. Any help would be greatly appreciated.

July 28, 2009
by wayward
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I have a few screens from broken Palm Visors. Good luck getting one of those to work. I searched the land for any information about them, and the best I could come up with were hobbyist sites modding Palm to add an SMD LED or some such. A few hobbyists wrote on their webpages that they wish they had a datasheet for the LCD.

That being said, we could snoop inside a working Palm and try to figure out what's happening with the display leads when it is operational (it's an LCD so I suspect there's some AC component to it) but, in all honesty, I would rather buy a documented graphic LCD and use a PS/2 touchpad as input than try to divine how to drive a bare graphical LCD display.

July 30, 2009
by BobaMosfet
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wayward,

I have pretty good luck finding obscure datasheets for LCDs and other components. If you can put a sharp picture of both sides of it, showing the whole thing and contacts, I might be able to find you what you need.

August 10, 2009
by wayward
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BobaMosfet, if you really have nothing better to do, then I might as well take up on that offer :)
I actually have two displays. Sorry that I can't take a photo at the moment; they are completely unmarked except:

- manufacturer's name on the side (SHARP);
- two stickers with two markings each at the top of the backside:
  [ B0085A     11032428Y ]  and  [ LQ031B1DD04  11004311 ]  -- display #1
  [ B0085A     09002988Y ]  and  [ LQ031B1DD03  09014455 ]  -- display #2

If you actually come up with something, I am offering to send you one of these touch-displays as a token of gratitude :)

Zoran

September 17, 2009
by rusirius
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Wayward, Sharp makes several LCD display that begin with the LQ031 part number... So no doubt that's the LCD... That's not really a concern though, except that it eliminates that as a possibility for what we REALLY want to know, which is what controller it uses...

  So one would guess the controller is denoted by the B0085A...  Not anything that I'm familer with... HOWEVER... Samsung DOES make a controller that's used to interface with a lot of LCD's that has a similar part number... That's the S6B0086...  Here's a link to a datasheet... http://www.longtech-display.com/FAQ/IC%20datasheet/S6B0086.pdf

 Those can be cascaded together to drive large LCD's... Given the size and ratio of the palm displays, and I'd be very surprised if that wasn't what was used to drive it...  It should at least give a starting point anyway!
September 18, 2009
by wayward
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Hey rusirius,

thanks for taking the time to respond! I finally gave up trying to drive the LCD directly, at least for now. I am not even sure I can generate 100V AC, which is what I think it needs (there's a "HIGH VOLTAGE" label on the Palm PCB's silkscreen next to where LCD power is connected)). And I am limited to PDIP IC packages only, so no go -- for now. :)

But thanks, anyway! If I do run across something, I'll let everyone know.

September 18, 2009
by rusirius
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I'd guess that the 100V AC is for the backlight... One of the tutorial videos actually describes using an inductor to generate the voltages requires, as well as a FET to control the frequency... Pretty simple actually... There's also tons of resources out there for calculating the value of an air core coil, so you can easily construct your own if you have some wire laying around...

Be careful though... An inductor in a circuit like that is capable of generating some tremendous voltages... They can easily do more than just "tickle" LOL...

September 19, 2009
by wayward
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Oh yes, that's why I'm not tackling those until I am ready. :)

September 19, 2009
by rusirius
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On a completely off-nerd-kits topic... When I was first getting started learning about electronics, I had just enough knowledge to be dangerous... I decided fixing CRT monitors would be a good place to start... I actually did pretty well, and made a little spending cash on the side... BUT... I'll never forget one of my first lessons... Even after discharging a CRT and pulling the anode off, they can over time build quite a voltage back up... When a week later you decide to put the anode back on and squeeze it together with your fingers would inserting it...

Well... Let's just say from that point on I never worked on a CRT without a clip-lead from the anode connection to ground... ;)

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