laptop motherboard soldering

[ShadyK]

Hi again everyone

because i got such good and helpfull responses from my last post. I would really appriciate some help again please.  I want to add LEDS to my laptol case and keyboard. The case modding is not a problem. Its knowning 100percent were to put the cables. Will i just test the connections to my battery connector and run the cables of there with a transistor on the negative? Thanks for the help in advance.

[Terabyte2007]

What are these LEDS for? Power, HD,

[ShadyK]

I would have leds to illuminate my keyboard and then just tk moddified my casing

[Simon123]

Why dont you solder it to usb?

[G7PSK]

Most laptops will have an unused  USB port on the motherboard that you could use without having to use one of the physical port outlet sockets, have a look at the laptop schematic or circuit diagram.

[ShadyK]

There will be about 6 leds in total will i have to use a transistor ? And i am a noob at this so would it be easier to solder to usb?

[Terabyte2007]

You should not need a transistor, but you will need some current limiting resistors depending on where you pick up the Vcc. Coming off the USB will give you about +5V or slightly less depending on your USB driver chip. Keep in mind that the USB will be limited in current (Ranging from apropx. 300mA - 500mA) so keep this in mind when you spec the LEDS and if you plan to still use this port for devices. Personally, I would come off the main +5V rail or regulated output but this depends on your skill level. If you want to get really crazy, you could add some logic and watch for a keypress then turn on the LEDS for a predetermined amount of time with a timer chip, then turn them off again! 

[Simon123]

Will you have a switch, so you can turn leds on and off?
But be carefoul, not to desolder any smd caps and resistors while doing this.

[ShadyK]

Oooo like a mobile phone keyboard thats got me intreaged how would i go about doing that then? This is my practising ya see im just starting out so i want as much expeirence as possible

[Simon123]

What type of laptop do you have?

[ShadyK]

Well its a pooh one because i dont eant to brake my proper one its a samsung r519

[Simon123]

Thatl be hard in thin laptop like that.
You could try el wire(pop the buttons of and lay the wire around), but the inverter is pretty big.

[ShadyK]

Im still a little bit new so could you explain that a bit more for me. Could i not just run the wires around the casing to where i want the leds to sit? And hot glue the leds in place? Or would that not work?

[amyk]

Be careful with EL wire, high voltage high frequency can cause EMI issues especially with things like the trackpad.

[Simon123]

You could use leds, but for this small keyboard itll be tight fit.
And how would you get wire from inside to outside? You proably wont drill holes in keyboard?

[ShadyK]

Yeah thats what my problem is going to be the case modding but i can fathum that out it was mainly the wiring and the powering thats all because if my keyboard is too thin i was going to mod the top part with leds in too.