slow fadeing leds

Ask and answer questions, share tips and resources for installing lighting and other electronics in your models.

Moderators: Sparky, Moderators

Post Reply
User avatar
chiver
Posts: 645
Joined: Wed Feb 08, 2012 5:25 pm
Location: Trenton

slow fadeing leds

Post by 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?
KEEP CALM AND CHIVE ON!!!
RossW
Posts: 198
Joined: Wed Oct 02, 2002 1:04 pm
Location: Toronto, ON

Post by 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'.
User avatar
chiver
Posts: 645
Joined: Wed Feb 08, 2012 5:25 pm
Location: Trenton

Post by chiver »

thanks i'll give that a try
KEEP CALM AND CHIVE ON!!!
User avatar
Tchail
Posts: 4330
Joined: Tue Mar 04, 2003 8:40 pm
Location: Nowhere in Particular

Post by Tchail »

You might want to try the Beacon Simulator from Ngineering:

http://www.ngineering.com/lghting%20eff ... ilroad.htm
“In the beginning the universe was created. This made a lot of people angry, and has generally been regarded as a bad move." Episode 5, The Hitchhiker's Guide to the Galaxy
User avatar
chiver
Posts: 645
Joined: Wed Feb 08, 2012 5:25 pm
Location: Trenton

Post by chiver »

RossW wrote: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
Tchail wrote: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
KEEP CALM AND CHIVE ON!!!
User avatar
chiver
Posts: 645
Joined: Wed Feb 08, 2012 5:25 pm
Location: Trenton

Post by 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
KEEP CALM AND CHIVE ON!!!
Grumpy Popeye
Posts: 1011
Joined: Fri Jul 12, 2002 9:11 pm
Location: Lower left hand of Canada, surrounded by a moat!

Post by 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
The rakishly handsome artist formerly known as Darph Bobo
RossW
Posts: 198
Joined: Wed Oct 02, 2002 1:04 pm
Location: Toronto, ON

Post by RossW »

chiver wrote: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?
User avatar
chiver
Posts: 645
Joined: Wed Feb 08, 2012 5:25 pm
Location: Trenton

Post by chiver »

I'm fine with it just turning off, and I wanted to avoid pic controllers. Only because I'm not that skilled yet
KEEP CALM AND CHIVE ON!!!
mattw
Posts: 31
Joined: Fri Dec 04, 2009 12:14 pm
Location: North Carolina

How about a slow fad on and off in a timed cycle??

Post by 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
"Please excuse the crudity of this model,.... I didn't have time to build it to scale or paint it"
User avatar
chiver
Posts: 645
Joined: Wed Feb 08, 2012 5:25 pm
Location: Trenton

Post by chiver »

If your looking to use a single led this might help

http://www.jameco.com/webapp/wcs/stores ... 2123637_-1
KEEP CALM AND CHIVE ON!!!
mattw
Posts: 31
Joined: Fri Dec 04, 2009 12:14 pm
Location: North Carolina

Post by mattw »

chiver wrote: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...
"Please excuse the crudity of this model,.... I didn't have time to build it to scale or paint it"
Post Reply