LED's connected to Amp outputs?

[Frostedflakejake 148]

So thanksgiving is coming soon which means no school for us who are still in it! Which for me means being bored out of my mind. I also just so happen to have 500 blue LED's handy. Out of all the things i could do with them, i decided to see what it would be like to put a bunch of them in the back of my explorer! For getting power to them, i was thinking about wiring them up in groups of series and then connecting them directly to the speaker wire input on the SAZ-3000d. Since i don't know nearly enough about that, i was curious as to whether that's a good idea or not (whether it will break something or not!). So the idea is that when the bass is really loud, the amp produces more voltage which i'll have the groups of LED's wired in series so that when the amp hits that voltage associated with loud bass, the LED's will light up! That's the general idea. I don't know the current draw of the LED's... i know for LED"s in general it's extremely low. But there will be around 480 led's back there..

So will this work at all? Essentially i'm daisy chaining groups of around 7 led's together and then running the positive and negative of those into the amp where the speaker wire plugs in. I also want this to happen while the speaker is hooked up to the amp as well.

If this ends up being way too difficult then i'll just hook them up to the secondary battery with a on/off switch. I can solder, but i do not know how to make circuit boards.

let me know if i need to input any more information.

Thanks!

[Sir-Lancelot 216]

I would put them on a switch and hook up to the battery.

I would want to turn them on and off personally.

[altoncustomtech 773]

I second what lance said.. If you're wanting them to flash with the music, do a little search on the net. You'll need some extra circuitry to pull that off, but with some careful designing you can make it so that certain lights light up at certain frequencies so that when you play music it looks real neat with the effect the light is moving and dancing.

[sefugi 166]

Sounds like a cool idea, check this out and the videos and see if this might be a solution for what you are looking to do: http://www.oznium.com/12v-remote-dimmer-strobe-switch I have purchased many things from this site and have allways been happy. If you have questions they seem to be very helpfull.

[CrazyKenKid 64]

umm aren't LED D/C and not A/C?

as for your idea of having them flow with the music more stuff is involved i looked into it one day and said screw this! lol. but i may some day do something like your idea just i have no time for it now.

and i think there was a thread about this already I just can't remember the name of it off hand. Hell i think i even started a thread like this back in the day lol

[CrazyKenKid 64]

I think he wants them to get brighter as the bass notes hit hence why he wants to hook it up to the amp so when the sub hits the lights hit also. but the amp outputs A/C and i think LED are 12volts D/C

Sounds like a cool idea, check this out and the videos and see if this might be a solution for what you are looking to do: http://www.oznium.com/12v-remote-dimmer-strobe-switch I have purchased many things from this site and have allways been happy. If you have questions they seem to be very helpfull.

[sefugi 166]

I also found this but it seems to have a limit of a 2 amp draw but you can check iit out here: http://www.oznium.com/cathode-music

[CrazyKenKid 64]

I also found this but it seems to have a limit of a 2 amp draw but you can check iit out here: http://www.oznium.com/cathode-music

holy cow you found one!! DAMN you rock!

still nto what i expected but still pretty cool!

[CrazyKenKid 64]

but here are some links i found back in the day!

the first one is easier to understand for me since i am in school for this type of thing

http://forum.allaboutcircuits.com/showthread.php?t=16014

the second one has a bunch of stuff

http://forums.makezine.com/comments.php?DiscussionID=2316

[cheese20323 13]

get power from the battery and signal to turn on from the RCA's

[altoncustomtech 773]

cheese is right.. the circuits that do the light control are 12vdc powered and use the incoming signal to vary the brightness of the led's by varying the voltage... Also, by using several op amp circuits you can have multiple outputs which will vary their output with frequency and signal strength. There should be PLENTY of audio controlled light circuits available on the web which are actually quite easy to build. Hell, we built dozens of them in my High School Electronics class 15 years ago, I'm sure there's better chips and circuitry for that available now.

[cheese20323 13]

Arent you majoring for an EE OP? You should know this.

[Frostedflakejake 148]

holy cow! I didn't expect this to blow up so fast!

Cheese - That's a good idea! But i already have a useless switch installed in my car that right now is connected to the front battery and then nothing else. So if i were to go the "switch on, switch off" route, i would already use the switch that's installed.

CrazyKenKid - The led's run up to 4 volts. They turn on around 2.8 but are dim to the point of being useless. As far as i know, it shouldn't matter at all that the amp is outputing AC power and not DC. Voltage is the same but you may be onto something with the current... I tested this with my little stereo in my room and it worked fine untill the LED's blew. I figured it was because i sent too much voltage to them but it could have something to do with the current... or pretty much 100 different things. thanks a ton for the links man!

Sefugi I think i'm going to go ahead and buy that Music Flash interface. Hopefully the 2amp rating is enough for 25 or so LED's and the rest will be connected via battery. After some internet searching, it looks likemost LED's have a current rating of 10 or 20 milliamps. I'm going to e-mail my LED supplier to make sure, although i don't expect an answer (purchased from Hong Kong seller on ebay). Thanks so much for the links!! Unless any of you guys can think of a reason NOT to buy that music and flash interface, i'm gonna buy one monday!

Edit: Mis-read the oznium site.

Edited November 13, 2010 by Frostedflakejake

[Frostedflakejake 148]

Cheese, i'm a first year EE student in my first semester of class. So no, i don't and quite frankly i don't think i should know it. I'm in school for EE so that i will learn how to do stuff like this. I don't even have any class that is EE specific right now. But thanks for the kind words!

[cheese20323 13]

Cheese, i'm a first year EE student in my first semester of class. So no, i don't and quite frankly i don't think i should know it. I'm in school for EE so that i will learn how to do stuff like this. I don't even have any class that is EE specific right now. But thanks for the kind words!

Haha my bro is didn't get anything til his 2nd year...but back OT....there was some guy on SMD selling some little converter thing that you can use for LED's let me see if i can find it.

[sefugi 166]

Sefugi I think i'm going to go ahead and buy that Music Flash interface. Hopefully the 2amp rating is enough for 25 or so LED's and the rest will be connected via battery. After some internet searching, it looks likemost LED's have a current rating of 10 or 20 milliamps. I'm going to e-mail my LED supplier to make sure, although i don't expect an answer (purchased from Hong Kong seller on ebay). Thanks so much for the links!! Unless any of you guys can think of a reason NOT to buy that music and flash interface, i'm gonna buy one monday!

Edit: Mis-read the oznium site.

Seems that all of the leds on Oznium's site are 20mA but some require a different voltage depending on color, don't know how that may affect your brand of led.

[Tirefryr 1,742]

Chances are you are going to overload them with current due their inherently low resistance. IT's almost a dead short, so you would need thousands of them to work properly without some form of circuitry control. It may work if you wire enough up and use a very very small amp just for them, but then you run into another problem. You get lights that come on and off due to the reversing alternating current, and get dim and bright due to the varying voltage coming out of the amp.

[scottxgtr 9]

Cheese, i'm a first year EE student in my first semester of class. So no, i don't and quite frankly i don't think i should know it. I'm in school for EE so that i will learn how to do stuff like this. I don't even have any class that is EE specific right now. But thanks for the kind words!

bookmark this thread for a revisit in 4 years and youll be amazed at how much youve learned. especially the differences in AC and DC

that said, i wouldnt hook them up to the amps output. thats asking for trouble. and leds vary in voltage a little but most go up to 4v. sometimes if you buy on ebay they solder a resistor and some wire and call it "12v ready" so make sure you know exactly what you have. any mistakes will result in dim leds or burnt leds.

[Frostedflakejake 148]

Thanks for all the input! And yeah cheese, the way it works up here at Michigan Tech is they try to postpone classes specific to a type of engineering as long as possible. Our first year is a engineering route that can be applied to any pretty much any engineering type so if we decide to change, it won't be a huge problem! So... yeah, I don't know much at all about electrical anything and i hope i didn't come off sounding like i did!

so i figured a direct hook up to the amp would be a bad idea, I was just hoping it would be a good idea!! I've tested the LED's, so far all of them can take up to 4.2 volts and i haven't tested any higher. They are not 12v ready either, but i sure as hell wish i was. I bought them because they were 14.99 for 500 of them and so far they have all been working flawlessly!

I've checked out oznium alot, but their raw products (the L.E.D. strips and such) are too expensive for me but it seems as if i may have to buy them anyways.

But if i use the Music and flash interface it seems as if the L.E.D's will still basically be hooked up directly to the amp, right? Which would still cause a problem for me, right?

[sefugi 166]

Music and Flash interface does not connect to the amps, check this info: http://www.oznium.com/forum/topic15503

[Frostedflakejake 148]

Ah man, i'm just screwing up a whole lot tonight. I watched the video and i didn't realize he was just jacking power from the amp for the turn on of the Interface. But i'm still confused on how and where i would hook up my L.E.D.'s to receive power. i think directly to the Music and flash Interface, Right? I'll probably shoot them an email about it as they are probably the only ones that know!

Edit: threw in the e-mail bit

Edited November 14, 2010 by Frostedflakejake

[95Honda 486]

They will work just fine on the output of the amp. A/C or D/C doesn't matter, they will forward bias/reverse bias faster than than your eyes will ever be able to detect. They will just light up with the bass (assuming you have a low pass filter, pretty sure you do with a class D.)

You'll just need to use a resistor to drop voltage and keep things safe. The resistor value will depend on your led forward bias current rating. If you aren't sure, just start with something high like 10K or so and work your way down. If you are using very high output leds, the resistor will be much smaller. Try and use a 1/2 watt or higher at least for the resistor, a few watts will be better, depending on how many leds you will use.

Also, you could just use a ton in series, that will be fine too, jst make sure you hook up the polarity right, if you put one in backwards, there will always be one reversed bias and no cuurent will flow.

I use leds in my amps I build straight of of the mains input (50/60Hz) with a dropping resistor and you could never tell it was driven by AC.

The leds will blow up before you hurt an amp with an output stage like that....

[Frostedflakejake 148]

Thanks 95 honda!

But i'm slightly confused. If i'm trying to run 4volts to all my L.E.D.'s, and at the moment, a pure sin wave at 50 hz mades the amp output around 45 volts at the volume level that i choose as my max, isn't that not a whole lot of L.E.D.'s in series? I don't know much of anything about circuits but is it true that if i hooked one L.E.D. directly to the amp and cranked my volume up, it would get 45 volts, right? And if i hooked two up in series and then hooked that up the amp, both L.E.D.'s would get 22.5 volts, right? and if you follow that logic all the down, it would end up being about 11 L.E.D's in series directly connected to the amp in order for each L.E.D. to achieve 4 volts. Of course this is just an example because on music, the amp doesn't get to 45 volts at any comfortable listening level but you get the point. Why doesn't that work?

[johnecon2001 82]

umm aren't LED D/C and not A/C?

as for your idea of having them flow with the music more stuff is involved i looked into it one day and said screw this! lol. but i may some day do something like your idea just i have no time for it now.

and i think there was a thread about this already I just can't remember the name of it off hand. Hell i think i even started a thread like this back in the day lol

You can get both iirc.

[CrazyKenKid 64]

aww that i didn't know!

umm aren't LED D/C and not A/C?

as for your idea of having them flow with the music more stuff is involved i looked into it one day and said screw this! lol. but i may some day do something like your idea just i have no time for it now.

and i think there was a thread about this already I just can't remember the name of it off hand. Hell i think i even started a thread like this back in the day lol

You can get both iirc.