Laptop Keyboard EL Panel Backlight


[nullpointr] wanted a backlit keyboard for his Asus Transformer Prime so that it would be a bit easier to use in low-light situations. He considered a few different options and ended up adding electroluminescent panels behind the keys.

Those paying close attention might wonder why we called this a laptop in the title. Well, it’s a tablet with a keyboard dock and that’s a mouthful. This actually really helps to simplify the modifications because the motherboard and other bits are all in the screen portion of the device. EL panels are also a nice choice because you can cut them to size and they still function. With a bit of case work, three panels were made to fit side-by-side.

The part that just isn’t going to make it in the original enclosure is the inverter that drives the panels. It’s the black box to the left. [nullpointr] added a USB-form-factor jack to the side of the case that allows the inverter to be disconnected quite easily. This way the Transformer Prime can still go with him on the road, it just won’t light up unless he also hauls around that add-on.

Way way back we saw someone do this with fiber optics and an LED. Unfortunately that project link seems to be dead so we figure it’s about time someone revisited the concept.

26 thoughts on “Laptop Keyboard EL Panel Backlight

  1. Hopefully nobody ever tries to plug a flash drive into his 10V USB port.. Great hack but terrible choice on connector if you don’t keep the USB lines 5v. There’s pretty much no configuration you can put that in that will keep the devices plugged in safe.

  2. Indeed, accidentally plugging another device in this “USB” port will certainly fry it, and just imagine what would happen if someone would plug that inverter into a regular USB port! At 5V, it would deliver a little less than 140VAC, but probably still more than enough to fry the USB controller.

    What you could do to somewhat prevent this, is to reverse the polarity out the power supply, and include an ultrafast fuse in the keyboard. With a little luck, the ESD diodes in a regular device will cause an overcurrent, hopefully blowing the fuse before destroying the device. A reverse diode across (or a diode in series with) the power pins of the inverter would prevent damage if it plugged into a regular USB port.

    I can’t really see if the light actually lights up the characters on the keys, or just the outline.

    It’s a rather nice build, thought!

  3. Hi, I built this “thing” and wanted to clarify a few things.
    yes, I’m totally aware about the danger of using a standard USB plug. That was intended. Since only I use this tablet, there should be no danger for me plugging somthing in the wrong port. Also, having this “USB Killer” is a king of BOFH way of teaching people not to plug shady looking USB devices into their notebooks.
    As for having 140VAC underneath the keyboard: I did what I could to keep stuff from shorting out but I’ll have to take it apart given some time and look for wear on the tape and isolation I did.
    There is no light comming through the keys themself. Only the outlines are lit but that’s enough.

    1. Great point, you’re the one in charge of it, so to hell with anyone else plugging items into your property. I should have added something like that to my comment as I agree, use what you have on hand, but for the love of god remember it’s not just a normal USB port!

  4. For people who do not want a mac, but secretly do…..
    I don’t think added yet another poorly imitated feature will make this stuff better.
    No ambient light control and no see through key decals will make this even harder to use in low light.
    You don’t have to run OSX on the hardware you crave for, so just stop pretending…

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