5v light question

[NoBonus]

Okay, I still have not wired up a LED light system to my 5v output on my KeyWhiz Eco.  Here is my question.  I only want to light a translucent blue trackball and want the simplest and cheapest option available.... can I use a 6v flashlight bulb? or will that be too dim?  Is it a must to have a blue light? or will white light do?

[TOK]

A standard flashlight bulb will make a lot of heat. If you want to go with 12v LED's, they're readily available at auto parts stores. I got a 3 pack for under 5 bucks and wired them right off a 12v lead on my computers power supply. I put all 3 in a piece of cardboard under the trackball, and they light it up very bright.

[NoBonus]

I just want to run the light off of the 5v supplied by the keyboard cable, not directly from the computer's power-supply (thus the 12v option is out).   Now when you say a lot of heat, how much heat are we talking?

[Popcorrin]

I don't think you would want to drive a flashlight bulb from your keywhiz.  It would draw too much current.  Instead I would use an led, preferabbly a superbright, and either blue or white should be fine.

[NoBonus]

so a LED is the best option, but where should I attain one and what resistor to pick?  I need a little help... 

[romperwomb]

so a LED is the best option, but where should I attain one and what resistor to pick?  I need a little help... 

Check out LSDiodes: http://www.lsdiodes.com/.  They even have a helpful tutorial on powering LED's.

[RandyT]

Here's a word of caution:

Never hook up an incandescent bulb to the 5v of your KeyWiz.  The 5v for the KeyWiz comes straight from the PS/2 port, and if you blow the fuse in there, it'll be a major pain to make the port work again, if it's possible at all.

In other words, if you like your motherboard and want it to continue to be servicable, don't hook up power hungry stuff like lightbulbs to your PS/2 port.

LED will be fine as long as you don't use too many.  The number will vary with the model of motherboard in question, but 5 - 8 LED's shouldn't be a big deal.

RandyT

[quarterback]

Never hook up an incandescent bulb to the 5v of your KeyWiz.

[NoBonus]

I just heard 100 mA should be the ceiling, but that is just what I heard.

[RandyT]

I just heard 100 mA should be the ceiling, but that is just what I heard.

I would also consider that "safe", but the max will depend entirely on the motherboard as there is no standard.  The computer in my living room has a 3amp fuse on it, but I'm sure that is not typical.  Also, I would expect older computers to be more sensitive than newer ones.


RandyT

[quarterstringer]

I used the blue lazer led canon from SV Compucycle to light up my blue translucent trackball. I installed it with the molex connector, I think it's 5v but not totally sure.