So you guys know those little PC speakers you get that comes with just about every case you buy? You know those one's that go BEEP every time you turn on your system or worse yet go BEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEP when something just dies on your rig. Well let me now tell you my ever loving hatred of these blasted things. Sound travels at approximately 700 MPH but the bullet coming from the barrel of my SKS does about 1500 feet per second, and that's the way these little speakers sit with me.

Staying on topic, last night I ran into a box of a dozen or so of these that I have ripped out of systems along with a bunch HDD and power LED's, and this got me thinking. I want to take out the speaker part and put an LED in there that would blink out whats wrong with my PC instead of hearing BBBBEEEEEEEEEEEEEEEEPPPPP.
Now I'm not the biggest genius when it comes to electricity, and in fact my knowledge of electricity stops at the fact that an electrical current flows from positive to negative or negative to positive if you feel like being a mechanical theorist. I need to know what I need besides the obvious LED, transistors, resistors, diodes? For the record I do know how to solder.

And to those of you that feel it necessary to use this , go dilly dally some where else. I spent 3 hours on Google last night looking for something similar or exactly like this.

Well what you need is a multimetre to check what voltage you are getting out of the pad where the speaker used to be. it might well be 6 or 12v which would blow an LED. If it is too high then you need to put a resistor in from of it, other than that you don't need anything apart from the LED (and you don't need a a diode because that is what an LED is silly:)) To find the size of resistor you need measure the current and then use our friend Ohm's law V=IR

Hope this helps

Oh and they take about 2v

if it was a buzzer or a piezoelectric transducer then you could modify it fairly easily because both of those work by applying a dc voltage to the sound device

a speaker driver is completely different in that you feed it an alternating voltage (the shape of the wave)...

i'm pretty sure a system beep is a square wave... at any rate, all you need is a sound-to-light circuit

A standard LED usuly wants 3.3 volts. (but they are perfectly at home running at 4-5 volts which is more than likely the voltage running to the speaker)

If you have a multimeter check it out, if not just solder the long leg of the LED into the red wire and the short leg into the black wire. (I think, if it doesnt swap it.)

That should be all you need.


:edit: NRG's right, its a different electric wave, but it should work anyways, the LED will just flicker instead of being a constant wave (I believe, Soldering an LED in would be the fastest way to test it.)

So you want:
BEEP length | LED blink length (- equals 1 second on)

So BEEP would be -
BEEP BEEP would be - -
BEEEEEP would be -------
BEEP BEEP BEEP would be - - -
and so on...

Seems like a neat idea...

Yea sort of like a Honda ECU that flashes out codes for trouble shooting, that where I got the idea from.

On another note thanks for all your help guys, I really appreciate it, but I have one last question, particularly for hardnrg.

Do you think this would work?

http://www.electrokits.net/electronics/aud...ce=FROOGLE-FEED

Again thanks for your help guys.

that circuit needs mains AC...

i was thinking something more along the lines of this: http://forums.overclockersclub.com/index.php?showtopic=67535

So I'm about to double post here (ban me later), but I just wanted to give an update to this little idea of mine. I found some LED's from an old antec sonata laying around that had some resistors already put on them. So I just cut up some wires and spliced them together. I'm happy to report that it works! The LED's give off a faint glow when the comp is on, but when the loud beep hits they light up nice and bright then go back to there faint glow. I've been able to produce long and short beeps so far and it seems like this is going to work quite well. Just thought I'd give you an update and an insight into what boredom can birth.

there should be 2 wires coming off the case that say's "SPEAKER"thats a 3 prong end and you should have a power led(Usless so us that one) On the end of it should say "Pled" or somthinh like that(refure to your case's maual to find the wires) but that pled end should be a 3 pronged end as well.... now just swap around and there you go.... another way is to go get a led and a resistor and find the speak and replace the speaker with the led and resistor



Oh and thx for using the post I posted about the audio to blinking led's

ahhh ok I see. I'm going to DC the ghetto rig I have up right now and I will make that little circuit there just to be on the safe side. Thanks for your help and

If you're gonna use that circuit, please do use resistors before or after the LED(s). I'm quite the electrical noob, but to me that looks pretty much like a sound activated short circuit

I know this is a little bit off topic but him mentioning those speakers made me think of what I like to do to them because I hate them...I hook them up to my reciever in my room and blast the sound until they smoke...

When I was younger I used to 'feed' LEDs off the back of audio speakers to achieve a 'strobe effect' you could do this and have the best of both worlds eh?

Alternatively, once you've determined the voltage triggering the speaker, you could use a 1/4W resistor to step the voltage down to whatever your particular LED specifications required

How about a SPDT switch and route the 'output' to either the speaker or LED? Hmmm... sounds like a project