G4 Handle Strobing Light Mod

Posted by: Jmp478

G4 Handle Strobing Light Mod - 05/20/08 04:41 PM

I've installed White LEDs into the small crevices in the clear acrylic handles.
I'm trying to get the lights to copy the strobing light in the power button. How would I do that?

I'm thinking I could make a small current amplifying circuit and connect it to the strobing power LED. Anybody have any ideas how to set it up? confused
Posted by: BigO

Re: G4 Handle Strobing Light Mod - 05/21/08 07:28 AM

That is an excellent question. I wish I knew, and I really hope someone answers you because I'd love to tap into that too!
Posted by: oojacoboo

Re: G4 Handle Strobing Light Mod - 05/21/08 11:42 AM

you should be able to tap into the same line running to the power button, assuming there are more than one, and amplify that signal.
Posted by: Jmp478

Re: G4 Handle Strobing Light Mod - 05/23/08 12:17 PM

Yeah, That's what I was thinking. There are a couple problems though.
The computer shuts off the power supply when it goes on standby, so there would be no power for the amplifying circuit. And even if it didn't, the glowing light would keep me up at night.

I could run the LEDs off of the 5V of the power supply when the computer is on, and when on standby, have the case LEDs connect to the power buttons circuit. That is, if the power button gives enough current to power all 4 LEDs.

How would I make a circuit that would switch power to the front LED when the computer's power supply is off?
Posted by: soundmann18

Re: G4 Handle Strobing Light Mod - 05/23/08 04:53 PM

Perhaps something like this would work (in the preview here it looks like this is cutting off the right edge of the pic, which is just a box for the LED circuit):

The diodes prevent power from the supply going into the button, which would probably be bad. But it also means that when both are on, the led circuit is getting double the power, but you may be able to regulate that in the led circuit, I should probably know how to do that, just graduated as an electrical engineer ... but that would take a good deal of thinking that I'm not prepared for now, as I said, just graduated, my brain has earned a break!
Posted by: soundmann18

Re: G4 Handle Strobing Light Mod - 05/23/08 05:24 PM

An update:

I just read the rest of this forum, and here's a possible idea for the amp circuit (again, its cutting off a bit on the right, that's just a Ds for where the leds are):

So the + and - on the left are the + and - at the right of my last picture. - is tied straight to ground and + goes to the negative input of an op amp. The positive input on the amp is connected thru R0 to ground. The amp is powered by the voltage on the lines. There is a negative feedback connected thru RF from the output to the negative input. Ok, the ratio R0:RF determines the amount of gain, you want this to be high gain, I don't remember exactly how this works, if high gain is from high R0:RF or low. This high gain forces the signal to the rails, so that the output is equal to the power on the power inputs. As I'm typing this, it seems to me like this circuit doesn't actually do anything, we're only getting out what we put in. So what it really needs is an independent power source that is slightly more power than what you want on the output. This way, if you have the high power of both supply and button from the last picture, the gain from the amp rails the circuit so that it is fully on. When you have only the power of the button, the gain is enough so that on the peak of the pulse the signal barely makes it to the rails, and then falls off as it loses power.

I'm not really sure where you can get that independent power, but I may have an idea that could work. Let me know if this much makes sense to you and if I can clear anything up.
Posted by: Jmp478

Re: G4 Handle Strobing Light Mod - 05/23/08 05:33 PM

Wow... You've lost me, man. I'm not really worrying so much about amplifying it now, though. Hopefully, the current that powers the front LED will be enough to light the other 4 up at least a little bit.

In other words, I want the lights to be on full power when the computer is on. When the computer is on standby, the circuit powering the front LED will keep the LEDs lit dim. I don't want the lights to be too bright when I'm sleeping.
Once I open up my computer and get into the front LED circuit, I can see if it has enough power to light all 5 LEDs.

What I'm mainly concerned about is that the power supply will pump power into the front LED circuit, then into the logic board. I just want to be certain that your first schematic will work in protecting the rest of the computers circuitry before I actually hook everything up.