Using A Cellphone LCD As Auxiliary Linux Display

[Neil] is driving this Siemens A60 LCD using a parallel port on his Linux box. He likes this module because it has an integrated LED back-light, controller IC, and the pads are large enough for a human to solder. He notes that the screen runs on 2.9V, which matches the forward voltage of the LEDs used as back-lights. This means it is possible to use one f the LEDs as a shunt to drop  incoming voltage down to a safe level for the controller. In fact, that’s what he did. The data lines are connected to the parallel port along with some current limiting resistors. The LEDs are connected with resistor calculated for maximum brightness, with the output from the LED used as the source voltage for the LCD controller chip.Whether you want to use one of these screens with a PC or something else, the code that [Neil] worked out should provide the information necessary to do so.

The Nokia cellphone LCD post inspired [Neil] to send in a tip about this project. If you’ve got well documented hacks that you’re just sitting on why not let us know about them?

31 thoughts on “Using A Cellphone LCD As Auxiliary Linux Display

  1. The one that’s always interested me is the iPhone “retina display”. With it’s high dpi, I can think of some neat projects it could be used in. There are lots of places online where you can, apparently, pick them up separate from the phone as replacement parts. Unfortunately, I’ve been unable to find any information on what communication format they use. If it’s something simple like the LVDS used by most LCD monitors then you can pick up LVDS-to-VGA converters.

  2. This is so cool. I would love to see some complete DIY pocket computers on here, using cell phone parts and linux and wifi cards and stuff. In my mind that’s the ultimate hacker gadget.

  3. @mixadj: I will support such a project as long as it uses an ARM processor. ;-)

    Bonus points if it also uses the “retina” display. Me too has wondered how hard it would be to integrate one into DIY electronics. 960×640 is a hell of a resolution, there are netbooks with less pixels.

    1. I’d only support projects with Intel processors. The reason is that most processors and boards will fry if you remove the heatsink while it’s running while an intel processor will just slow down your processes to a crawl to save your system.

  4. I don’t understand why everybody is so enthusiastic about the iPad display with its high resolution… You can get a replacement display for e.g. The old HTC Touch Diamond which has 640x480px for 15-20 bucks.

  5. @h3po: On top of it’s high resolution, the “retina display” is also supposed to have higher image quality and better view angles than most other displays on the market. The tech it’s made from is also supposed to have a much lower response time which is important for games and video.

    If the only display I could get to work was the HTC Touch one I’d work with that. Unfortunately, I’ve never heard of anyone figuring out the communications protocol for that one either. Unfortunately, smartphone displays seem to be completely undocumented and, I fear, all use non-standard communications protocols/interfaces.

  6. I’ve used displays from the siemens S65 phone. There is some documentation available. They used to be cheaper than normal 2×16 character displays, but hard to find now.
    It was greater resolution, easy to solder. The drawbacks were, of course, the 2.9V power supply(easily usable with dividers) and the 3 series white leds for display.
    @SRKRS are you the project builder? I can help you with the mirroring. contact me.

  7. @Colecoman1982 VGA is analog interface. It was good for CRT monitors, it is not usable for digital displays.

    Using displays from mobile phones(especially higher end ones) is probably near to impossible to home user. The interface is probably some custom serial/parallel high speed, hardly usable with smaller micros(remember how many hundreds of MHz your phone CPU is running at?) Plus, there’s the software part, there is no reason why there should be any info on this published from the phone/display manufacturer. And reverse engineering gets rather complex.

  8. @bogden: Yes, I realize that VGA in analog but converting to that, or DVI, from the digital interface used by the base panel is needed in order to interface the panel with a traditional PC (which I, personally, would find useful).

    I, also, realize that the actual interface used is likely to be highly custom. On the other hand, these panels are manufactured by the same companies that make full size monitors and general purpose panels. It’s possible that the engineers that designed them stuck with a common format like LVDS or TTL for simplicity’s sake.

    If that were true, then it should be possible to get an off-the-shelf VGA-to-LVDS/TTL boards to work with it. The problem is, of course, that without any documentation, the only way to figure out if this is the case would be to reverse engineer the interface. Unfortunately, I lack those electrical engineering skills and keep hoping to find that someone might have blazed those trails already.

  9. you are missing a very great thing: vga, dvi and the others are ‘dumb’ interfaces. All they do is send each frame pixel by pixel and continously, in digital or analog and at whatever voltage levels.
    A phone display has to be energy efficient, information is not sent contonously. The interface is also ‘smart’. The cpu ‘talks’ to the display and it talks back. Some tipical conversation might be: goto that part of the screen, select a regtangle x by y pixels. Now start filling it wiith whatever pixels i tell you to. And thus maybe a button is redrawn on the display.
    Therefore no possible simple adaptation.

  10. I can see that being the case for basic cellphones where they have a limited feature set. (what you are describing sounds, very much, like how the industrial touchscreen “smart displays” work in automated systems here at my company). However, I don’t think that would work for a smart phone, like the iPhone, where the display has to be able to do many of the dynamic things that a real PC display does. Also, because, by their nature, LCD/Plasma/etc. screens don’t “refresh” in the same way old CRTs did, I would tend to expect that standard LCD panel interface formats, like LVDS, would already be taking advantage of any of these kinds of optimizations that are possible.

    Of course, these are all assumption and could, very well, be wrong. It is, however, why I think it’s reasonable to hope to see someone hack these displays into usability.

  11. FINALLY!!!
    i had a project with a nokia color display but there are not too many schematics around.
    i remember that can be also driven by some lcd program (that shows useful info like cpu,hdd usage etc.)that works also on windows but i can’t remember it’s name.

  12. Hey, this project is pretty cool, i was wondering if it would work with a laptop screen. the MB is broken beyond repair but if i could manually hook up the pin connector for the screen to a video output source could i use it as a acreen?
    i believe the Sn is b141ew03, when i googled i i got the screen as a result.
    Ive been wanting to do this for a while but could really use help on it, thanks

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