button/light questions

[brihyn]

I'm slowly purchasing the parts and setting things up for a pin cab build. Yesterday was my work 5 year anniversary, so I've decided to use my gift cash to purchase a handful of the things i need.
Question on the buttons with leds...can I power those directly off the 5v line of my pc power supply? I'm looking for constant-on lights (just a couple of the buttons will be lit), so no need for an LED-WIZ.

[ChadTower]

You could, yes, but I wouldn't advise doing that directly.  5v is going to be used in so many places you're better off running a 5V transformer (like a wall wart) into a wiring block and then grabbing 5v from there. 

[brihyn]

Ahh, great idea, thanks!

[PL1]

I have to disagree with Chad a bit on this one.

You can easily use 5v from USB for the LEDs as long as you don't exceed 100 mA for an unpowered hub port or 500 mA for a powered/dedicated port or use the molex for 5v and/or 12v depending on the voltage/amperage requirements of the contactors/shakers/flashers you use.

I use 12v LED buttons from Paradise with a 5v USB power tap.

You can light 14 buttons and a 3-LED trackball drawing only 81 mA -- example here.

For your setup, you won't even need resistor R2.


Scott

[ChadTower]

Yes, you can use it for these LEDs.

A VP cabinet is going to have a lot more distinct +5v devices than this.  May as well set up a real +5v source and be ready for the rest of them.  Even if he's not using many now he will be eventually.

[brihyn]

USB seems like a nice option. I'm only plannign to light up the coin button and a launch button. but I could certainly seeing eventually getting to the LED-Wiz point...i may look around for a brick...probably even have one in my bucket of random "wall warts without homes"