How to make LED continuously change colour??

[limit6]

Hey all!  Does anyone know how to make an LED continuously change colour, like the one in this video?

[Govmnt_Lacky]

You would need supporting circuitry to do this. There are PICs and/or ICs specifically designed for this type of work.

Frankly... its a lot of extra work to go through for a simple on/off indicator 

[deadastronaut]

nip to your local poundshop....they usually have crap that has these colour changing leds in...

beware, they can cause noise in circuits .however IIRC i put a 220uf cap in para with it...when tinkering.seemed to cure it...


search ebay, colour changing led....

[robthequiet]

I have christmas tree ornaments that do that -- you might something at a dollar store, depending on which country you're in. From the looks of it it's just 3 button cells, a switch, resistor and led. I'm guessing that it's a special led that does the personality change all by itself. If I have this, I wouldn't bother building from scratch unless I want to customize the effect. I have not tried these but here is a site you might check.

[J0K3RX]

I find it sort of annoying.. Maybe ok in a psychedelic mind warp type effect that I only kick on once in a while when I'm totally baked outa my skull... 

[deadastronaut]

merry xmas.....

[Mark Hammer]

1) As noted, requires an RGB LED.
2) Requires at least some digital circuitry to turn on each of the elements in a manner to produce a continuous change in resulting colour.
3) Since the 3 elements are usually not of equivalent perceived brightness, it will require a lot of trial and error to find not only combinations of elements, but combinations of relative intensity for each element, that can produce a continuous colour change that appears to have overall constant brightness.

4) Not worth all of that for the little chuckle it brings.

That said, RGB LEDs are nice for using colour to convey multiple kinds of status.  For instance, a person could use the LED to convey LFO rate, with it pulsing green when in effect mode, and pulsing red when in bypass.

[J0K3RX]

no external controller necessary.. slow cycling
https://www.sparkfun.com/products/114

I happened to get maybe 10 or so out of a rubber bouncy ball toy that my kid had after the coin cell batteries finally died inside. I tore it apart and kept the LED's... you can actually see the microscopic nano controller inside the LED's if you look close at them.

edit: probably cheaper to get a toy and shred it for the LED's... I think we got that bouncy toy for a couple bucks at the dollar store and I got at least 10 LED's out of it...  Not sure why they used 10 cause 1 was enough to cause epileptic seizures! I was glad when the batteries finally died after being on solid with no turn off switch about 6 months later! It originally was only supposed to light up when you bounced it but that mechanism quickly became stuck in full on insanity mode Thank God it didn't make noise... Thank God!!! It lived out it's final weeks deep inside a dresser sock drawer where it died slowly and quietly as it sent out it's last beacons of madness alone and OUT OF MY DAMN FACE!!

[J0K3RX]

That said, RGB LEDs are nice for using colour to convey multiple kinds of status.  For instance, a person could use the LED to convey LFO rate, with it pulsing green when in effect mode, and pulsing red when in bypass.

For instance, if a person could use the LED to convey their mood.. when pulsing green they are happy, and pulsing red when in pissed off mode, a blue solid when sad, orange flashing when aroused, purple fade when sleepy... 

edit: no idea what color would convey hungry?

[Rixen]

when I was a kid I found I could make a red LED glow green if I pushed heaps of current through it. Then they would glow black. Permanently.

[robthequiet]

Or you could get UV LEDs for their own little spooky glow. Red and green make me hungrier than blue, come to think of it.

[deadastronaut]

yep, i ripped my slow changers from toys too...i never waste an led...

i converted some garden solar lights to have warm white leds, and also mounted slow  colour changers

in there too, so i have a choice when the colours annoy me....


funny lil quirk i noticed with colour changers is they always start on red

when turned on....just an observation...

[amptramp]

There are garden solar lights that do this but beware - the colour change is done by pulse-width modulating the current into the LED junctions and this causes noise to appear on the power lines.  It may be best to have a separate supply to avoid electromagnetic interference.

[vigilante397]

I bought a big bag of these off eBay a while back. They were pretty cool, but I eventually stopped using them because 1) they were noisy, especially in high gain circuits 2) the novelty wore off.