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Guide USB laptop keyboard light

Discussion in 'Modding' started by mattthegamer463, 17 Aug 2005.

  1. mattthegamer463

    mattthegamer463 What's a Dremel?

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    Yesterday i was having trouble typing while using my laptop in the dark. so today i decided to make a light on a flexible wire that hooks up via usb so i could see my keyboard. i know they sell these, but that costs money! I dont have money! so i needed to make my own.

    Tools:
    Plyers
    Soldering iron
    Solder
    electrical tape
    wire strippers

    Materials:
    wire
    thick wire so the led will stay in position but be able to bend and move.
    Heatshrink tubing
    USB connector
    White led
    resistor

    Step 1: Take the gameboy light and cut the flexible wire and led off the connector to the gameboy.
    2: strip the wires for the light.
    3: cut the USB cord about one inch from the connector.
    4: take off the plastic and coatings so you have only red and black wires.
    5: take the red from the light and the red from the USB and solder them together, then put heatshrink tubing around them. do the same with the black.
    6: if you dont have a gameboy light already, take a thick copper wire and wrap the leds wires around it and glue it to the usb connector. if you need to, hook a resistor in between the red or black wire spot. this is only needed if you need less than 5 volts for the led.
    7: wrap electrical tape or really big heatshrink around everything, or do whatever you want to it so it looks good.
    8: plug it in and see if it works!

    heres a picture of the one i made. it needs a coat of paint.

    [​IMG]

    Hopefully ive helped someone be able to see their keyboard when in the dark! thanks for reading!

    Matt
     
  2. hitman012

    hitman012 Minimodder

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    Good guide - a cheap alternative to buying one of those overpriced ones.

    By the way, you NEED a resistor for the LED to limit the current. You can calculate the value like this:

    R = V/I
    (supply voltage - LED forward voltage) / LED current

    The LED current is about 15-20mA for normal LEDs, and the forward voltage about 2.2v. USB supply voltage is 5v. Using these typical values (you'll need to adjust for high-brightness LEDs), we get:

    (5v - 2.2v) / 0.020 = 140 ohms.

    The nearest standard value that you can purchase is 150 ohms, which is just about right to keep the LED current at a safe value.

    Alternatively, you can purchase LEDs with resistors integrated into them for various voltages (Rapid UK have a fair selection) to save you the hassle of calculating the value etc.
     
  3. mattthegamer463

    mattthegamer463 What's a Dremel?

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    well, mine didnt have a resistor in it because i tested it without one and it worked perfectly, so i figured i didnt need one. will it blow out now? so far it hasnt though
     
  4. hitman012

    hitman012 Minimodder

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    I assume that the Gameboy light has an integrated resistor, otherwise it would have been toast with 5V subjected directly across it. I don't know what voltage it's designed to run at, but it should be OK.

    I never thought of making my own one of these though. I think I'll have a rummage in the parts bin tomorrow and put one together :)
     
  5. mattthegamer463

    mattthegamer463 What's a Dremel?

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    well i highly doubt that, because the gameboys 2 AAs only put out 3 volts, so it doesnt even need a resistor, unless they had one in that made it not run at 3V, because it still works and is brighter than when its connected to the gameboy.
     
  6. hitman012

    hitman012 Minimodder

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    Pretty much every LED requires a resistor because they have practically no resistance of their own. Connect them without one and they will burn out very rapidly due to too high a current.

    Try putting just an LED across the terminals of a 9v battery and it'll toast itself pretty quickly. You need a resistor in order to limit the amount of current flowing through the LED to about 20mA.

    Edit: I'm sure there was an article on here before showing a video of someone putting 12v across an LED with no resistor. It must not be back up yet.
     
    Last edited: 17 Aug 2005
  7. mattthegamer463

    mattthegamer463 What's a Dremel?

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    so, are you saying im safe or that its going to blow soon?
     
  8. hitman012

    hitman012 Minimodder

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    The resistor in the GameBoy lamp will be calculated to run off about 3v from the twin AA batteries. Subjecting it to 5v will increase the current flowing through it a fair amount, which will reduce its lifespan.
     
  9. mattthegamer463

    mattthegamer463 What's a Dremel?

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    by how much? i know they normally last for about 100,000 hours, so as long as its like 5000+ im ok with that.
     
  10. csTYCOON

    csTYCOON What's a Dremel?

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    Im loving these short "how to" do it yourself guides! Good on yeah man.
     
  11. Gascan1888

    Gascan1888 What's a Dremel?

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    if u still have the other half of the light, just plug it in and test how much is going through the wires with a volt meter and then that will tell u if u need a resistor :thumb: but this is an awsome mod, might have to go "borrow" my brothers and do it :worried: :dremel:
     
  12. mattthegamer463

    mattthegamer463 What's a Dremel?

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    my new motto is " why buy it if you can make it!"
     
  13. mattthegamer463

    mattthegamer463 What's a Dremel?

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    ok, a minute ago i finished adding a 100 ohm resistor to the light. now it wont blow, and its only slightly less bright.
     
  14. zmodder

    zmodder What's a Dremel?

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    u actually saw somethin like this in a dollar store and i bought like 5 lol they work great btw and are almost exactly the same as my cuz (he payed like $20 for his hahahaha)
     
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