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General Category => Your projects => Topic started by: alexander on December 17, 2011, 03:37:21 AM

Title: Fade in/out led aquarium lamp
Post by: alexander on December 17, 2011, 03:37:21 AM
Hello,

I am new here and from Austria. I have only recently started playing with leds but so far haven't done anything elaborate... I found this site searching for a fade in / fade out solution for an aquarium lamp and have looked at the "circuits" section which looked promising - and which is absolutely great by the way!

My problem is that I basically want to be able to
(a) dim
(b) fade in / out very slowly when the power comes on/off (over the course of 30 to 60 minutes)
what amounts to a total of about 30 to 60 10W emitters in several circuits (there will be different color led circuits so that the light mix can be controlled/varied). (Heat management is another story ;-))

What I have gathered so far is that PWM would be the best way to go - but other than that I don't exactly know to accomplish this. I also don't know if such a long fade-out would be feasible or if it would be best to use a programmable platform where I also set he time the leds are on 100% (which I basically wanted to avoid for reasons of my programming skills).

So I'd really like to hear your opinions/suggestions on this project idea.

Cheers & thanks, Alex
Title: Re: Fade in/out led aquarium lamp
Post by: D-the-Greek on December 18, 2011, 17:43:05 PM
Hey Alex,

welcome to the forum (newbee solidarity from a Greek) ;) sorry about my black humour btw...

That sounds like a really nice idea which i might think of implement my self as i want to start an aquarium myself.
Its going to look really nice fading leds in there.

I am sure that youll get some help (sorry but not from me because im new in this world as well...i just started reading about microcontrollers and i am a very long way far away...)

Only this circuit comes to my mind =>  http://pcbheaven.com/circuitpages/555_Breathing_Pulsing_LED/  but im sure someone will help with the solution on longer fade in/out time of 30/60 min (if i understood correctly)

 Greetings and welcome again. Dimitris
Title: Re: Fade in/out led aquarium lamp
Post by: kam on December 19, 2011, 08:45:37 AM
hello alexander,

PWM is one solution indeed. as far as i understand, you want this circuit to operate automatically in specific hours of the day, right? this can only be done reliably with a microcontroller.

now, if you just want to turn on a switch for fade-in and then turn this switch out for fade out, you can go with this circuit:

LED Fade-In Fade-Out Dimmer (http://pcbheaven.com/circuitpages/LED_Fade_In_Fade_Out_Dimmer)

It does not have a dimming potentiometer, but you can easily add one (check my conversation with Roger in the comments of this circuit).
Title: Re: Fade in/out led aquarium lamp
Post by: alexander on December 19, 2011, 17:47:23 PM
@Dimitris: thank you for your answer - no black humor detected ;-) Sorry for replying to this thread so late, my spam-filter filtered out the e-mail notification and I didn't check earlier...
Great that you want to start a tank! It's a very rewarding hobby. May I ask: marine or freshwater? Maybe we can both profit from the found solutions.

@Kam: Basically it wouldn't matter to me so much if the solution works with a timer switch you use between the wall outlet and the power supply. An "internal" solution I can put into the lamp housing would of course be more elegant, since then I would only need 1 cord going out from there. As I understand that would need a microcontroller. Regarding your link - I had watched the video ;-) but I was generally just worried if the "fade-in fade-out dimmer" solution would work for the long fade-in/out times at the high wattages, since as I understood the size of the capacitor is related to this.

Cheers, Alex
Title: Re: Fade in/out led aquarium lamp
Post by: kam on December 20, 2011, 08:18:45 AM
the capacitor is related to the time. You will need a HUGE capacitor and bigger re-r4 values. as for the high wattage, that is only subject to the transistor that you will use. The BD243 is powerful enough to drive 6 amperes of load for example.
Title: Re: Fade in/out led aquarium lamp
Post by: billkaza on February 28, 2012, 17:06:26 PM
Hello,

I'm Bill from Greece too.

I'm also interested for this project.Does anyone has a basic idea to start from?
Title: Re: Fade in/out led aquarium lamp
Post by: kam on February 28, 2012, 18:02:57 PM
you can start by building up the fade-in-out circuit first. then you add a timer. what exactly you want?
Title: Re: Fade in/out led aquarium lamp
Post by: billkaza on February 29, 2012, 08:55:12 AM
I have a led tape 2 meters 8.6W/M so 17.2W. I use an 21W ballast dimmer that has a 1-10v output that you can trim it using a resistor trimmer. I also have a timer at the power plug that just turn on and off the ballast at certain times(17.00 - 23.00).What i want is when turning it on to autodim(0-100%)from  17.00 untill 17.20 and autodim(100-0%) from 22.40-23.00.

Can i have this effect using this ballast or do i need to make the fade in and out circuit?
I need the fade in and out effect to last 15-20 minutes if possible.
Title: Re: Fade in/out led aquarium lamp
Post by: kam on March 01, 2012, 19:08:09 PM
oh i see. the time you require is very long, so i am afraid that these two circuit will not work for you (http://www.pcbheaven.com/circuitpages/LED_Fade_In_Fade_Out_Dimmer/). As for the ballast, you can hack it and see how it works. the trimmer probably works as a potentiometer which sets a voltage from one level to another. if this happens, then you can effectively connect the first circuit to the ballast and have your results.