slow fadeing leds

[chiver]

how do you get an led to fade in slowly once the power is on, and then fade out once its off? is it possiable to do this with out a micro controler?

[RossW]

You can try putting a capacitor in parallel with the LED but you may only get a fade in. I looked into this a while back (I wanted a hardware solution as opposed to using PWM via a microcontroller) and found some info by googling ' fade in LED'.

[chiver]

thanks i'll give that a try

[Tchail]

You might want to try the Beacon Simulator from Ngineering:

http://www.ngineering.com/lghting%20eff ... ilroad.htm

[chiver]

You can try putting a capacitor in parallel with the LED but you may only get a fade in.

i just tried that with an orange led and a 1000uf cap. nothing happened. the light just came on as per the norm. with a 9 v bat

when i do it in series nothing happenedd, no light even. tried it in series with a smaller cap and it lights the fads out very quick

You might want to try the Beacon Simulator from Ngineering

had a look and i wanted it to stay solid lit once on.

its for the blue glow of the warp drive and deflector dish

[chiver]

intresting though, when in parallel it come to life like normal but fades out slow when hooked up to a 5 volt wall wart

[Grumpy Popeye]

Tena Controls has exactly what you're looking for

http://www.tenacontrols.com/

I haven't used their products yet but Boyd over at Scifi Model Action is a fan

[RossW]

intresting though, when in parallel it come to life like normal but fades out slow when hooked up to a 5 volt wall wart

I think if you want to do a hardware solution for fade in and out, it's going to get tricky. I've seen some attempts on the 'net but haven't been able to reproduce them to my satisfaction myself. Besides, I use PIC microcontrollers for all my lighting now and you can program in a fade in using PWM (pulse width modulation). If you want it to fade out on turning off the power, though, that would be tricky (since you've just cut off power to the IC chip). Maybe a combination of the 2: a custom programmed PIC to fade in the chip (with a small trim pot to control the fade in timing) and a cap for the fade out?

[chiver]

I'm fine with it just turning off, and I wanted to avoid pic controllers. Only because I'm not that skilled yet

[mattw]

While you're on the subject... How hard would it be to rig a bank of led's to fad on and off.
Say a 2 second fad to on, hold for 3-4 sec and a 2 sec fad out and then continue on a timed cycle..

Thanks
Matt

[chiver]

If your looking to use a single led this might help

http://www.jameco.com/webapp/wcs/stores ... 2123637_-1

[mattw]

If your looking to use a single led this might help

http://www.jameco.com/webapp/wcs/stores ... 2123637_-1

Thanks I'll check it out...