Guide USB laptop keyboard light

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.



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

Matt

 

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.

 

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

 

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

 

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.

 

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.

 

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

 

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.

 

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

 

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

 

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 but this is an awsome mod, might have to go "borrow" my brothers and do it

 

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

 

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

 

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)