ok the plan, hook up a string of led xmas style lights(or several) to a stereo by connecting them to the speaker wires with the idea being that they will pulse with the music.
1st can I just wire the 3 string leds to the stereo by hooking wires from the stereo to the plug that goes into the wall?
2nd I have a few of these Products - IKEA with the paper removed, they have yellow leds that poke out of the main wire about 2 inches and look great but they also have some crackhead European plug set up, I can bypass that simply by not plugging the string into the plug that goes into the outlet. hmmm thats not really a question (they were on sale for $9.99 totally worth it for the lights alone)
ok I guess I am just looking to see if any dopers have tried this or any electrician types have any tips before I explode a string of leds or set my hair on fire.
Don’t do this.
It will never work - the LED lights expect 120v, and your stereo won’t put out anywhere near that much, unless it’s a super-high power unit, cranked to 11.
What you are trying to make is called a “color organ.” I’ve made several over the years - you don’t need a power amp to do this, just a bunch of band-pass filters and a way to drive the LEDs (a power transistor).
Here is a link for a kit: http://www.goldmine-elec-products.com/products.asp?dept=1064
I read a bit where someone did this, he cut the string down to 10 lights and hooked them up to his pc speakers…the lights working off a 120v ac plug are my concern, since the stereo would be a dc source, so if that part failed due to the plug I would need to clip the plug and go straight into the wires leaving me to figure out which of the 3 is t the hot.
and if it woulndt work why not try? its not like youre hurting anything…unless poster #2 is right then the lights blow but I would start with the volume all the way down and slowly turn it up til things started working or whatever happened.
What Beowulff said. The output voltage on an amp is typically 40-80V which is probably less than what you need. Also the frequency would be too high, realizing that lights plug into a wall socket are already being cycled at 60Hz without any apparent flickering. Lastly, the impedance of the lights may be way too low (causing the amp to blow) or too high (causing them to not light) for the amp which is generally designed to optimally transfer power at 4-8 ohms.
When was a uni student, I made one of those, and mounted the Green and Red LEDs across the top of a pair of amber coloured lab style safety glasses. The control box (with microphone and battery) hung off my belt. It was great for a fancy dress party, pulsing with the music.
I think there are two required elements in wanting to do this on your own.
One, you’d have to consider Ohm’s law with the specifics of your amplifier and LEDs.
And, two, you’d have to understand the odd nature of how LEDs use electricity. As you raise the voltage across an LED from 0, it uses very little current until you hit some threshold voltage (which is roughly the same number as the photon energy in electron volts, so maybe 2 for deep red and 4 for deep blue). Then the LED becomes conductive, and as you try to raise the voltage further, they will draw a great deal of current and then self destruct. So, typically, driving LEDs involves some circuit that can deliver a known current, often about 20 mA per LED in parallel, and adjust its voltage accordingly.