Breathing LED's

I have seen this effect in halloween masks but I do not know haw to replicate this breathing effect. I made these videos to illustrate the effect
No idea on how to do it. A little help?

I'm sure it is fairly feasible but I am missing the instructable please see these 2 videos (1 minute each):

Picture of Breathing LED's
sort by: active | newest | oldest
1-10 of 17Next »
Here's what you want:

No microcontroller or 555 required.

At the time of this posting, unit is $3 AU.
biteme5567 years ago
ya i have been looking for the same thing for a model i was working on but i couldn't find one that just faded on  and off in one color
westfw10 years ago
There are a bunch of circuits on the net based on a "standard" op-amp triangle-wave generator. Google for "Triangle wave generator led fader" Here's a representative circuit with what looks like some detailed tutorial info LED Throbber The dual op-amps used in these are cheap and pretty interchangable.

Other than that, I'd be inclined to go with a microcontroller-based solution like what everyone else is recommending, but there's significant overhead getting started. That "smart led" website is pretty neat.
LasVegas10 years ago
The LEDs your refering to have the effect chip built into them. The RGB LED is especially sweet, that it rotates through every color of the rainbow in various patterns lasting three minutes.
dejabox (author)  LasVegas10 years ago
Thank you for the Hint Las vegas, have you built anything like that? Man I'd really like to build that myself, where could I get that chip...
LasVegas dejabox10 years ago
You can only buy the LED with the chip built-in. Probably the easiest way to get it is in one of those LED Pens that cost about $5. That's cheaper than buying the RGB LED alone.
royalestel10 years ago
I got a pen a while back from a career fair that glowed and faded in all six colors. You could search for those online and hack it.
dejabox (author)  royalestel10 years ago
Thanks man, I'll try to search for it. I wanted to make the instructable for people like me who want to just build it themselves, I'll keep searching
alex_weber10 years ago

using PWM and a microcontroller could do the job. Pulse Width Modulation switches the LED on and off very fast. The longer it is on, the brighter it seems to the human eye.
Search for PWM and ATtiny, for example.
Or have a look at: http://todbot.com/blog/2007/03/25/smart-led-prototypes/
Kind regards,
dejabox (author)  alex_weber10 years ago
Thank you very much Alex!! Any idea on the price? I wanna buy the parts ASAP!!
1-10 of 17Next »