How to control LED light (DC) from outlet (AC)

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  #1  
Old 03-28-12, 01:35 AM
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Red face How to control LED light (DC) from outlet (AC)

Hi everybody,

I've got an LED light in my aquarium which is controlled by a toggle switch button. I want that LED light to be automatically controlled with a timer. For that purpose I've purchased a AC outlet timer an want to think of a way to connect that LED light switch to the timer.

I think that to make it work I would need some kind of relay that would on one end would receive 110V AC current whenever the timer is active, and on the other end of the relay it should just short the wire from LED switch button.

What kind of relay and what additional components would i need to make this work.

Thank you,
RUben
 
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  #2  
Old 03-28-12, 06:11 AM
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Is the LED light powered with a wall wart transformer?
 
  #3  
Old 03-28-12, 10:11 AM
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Yes, it is powered by wall adapter. The same adapter also powers the filter pump which is supposed to be always turned on.
 
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Old 03-28-12, 10:57 AM
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The same adapter also powers the filter pump which is supposed to be always turned on.
Are there two cords from the adapter or what? Does the adapter feed one and then the other is plugged into that.
 
  #5  
Old 03-28-12, 11:33 AM
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ray2047, let me better draw a picture.


I want to control the switch of the led button depending on if there is current flowing through the output outlet of the timer.
 
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Old 03-28-12, 02:22 PM
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My solution would be to use a separate adapter for the light. Use a plug-in timer and plug the new adapter into the plug-in timer. If your like me you already have a suitable adapter in your junk cabinet. Much simpler and probably cheaper even if you have to buy an adapter.
 
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Old 03-28-12, 03:23 PM
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I'd just want to reuse existing power system and just control that light switch button.
 
  #8  
Old 03-29-12, 05:52 AM
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This relay and this socket (examples) will work. You'll need to mount it inside a box. Plug the coil wires into the timer. Connect the LED switch wires to either of the "Normally Open" (N.O.) contacts.
 
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Old 03-29-12, 06:19 AM
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Could you not just plug in the wall wart to a switched receptacle?
 
  #10  
Old 03-29-12, 01:04 PM
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Rick, thank you for the links. That would definitely work.

One more question. I've just realized that the on/off switch a is a reed switch which is controlled by a tiny external magnet. You can see the back stick which has a magnet inside:


I'm thinking if is a way to create a small magnetic field in that spot from 120AC power source I wouldn't need to sneak into the aquarium filter pump to get access to that switch contacts. I would just mount that electrical magnet externally and the timer would turn it on/off
 
  #11  
Old 03-29-12, 01:07 PM
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pcboss, no, that's not goona work. As a mentioned earlier, that would also turn off the pump which I need to have running 24/7.
 
  #12  
Old 03-30-12, 06:44 AM
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Don't run 120vac power anywhere near the water unless you like poached fish.

I would perform surgery on the LED light and run two wires from the switch to the relay.
 
  #13  
Old 03-30-12, 03:40 PM
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What if I use an adapter and bring the power down to 5-9 volts? Would it be safer to mount the electromagnet in that case? It should be as small as 1/4 of an inch in diameter. I should be able to cover the elelectromagnet with epoxy to make sure no water reaches the contacts.
 

Last edited by stickshift; 03-30-12 at 03:42 PM. Reason: removed quoting of entire post
  #14  
Old 03-30-12, 04:09 PM
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I've suggested a simple easy solution already. Can you explain why you need to make it so complicated?

http://www.doityourself.com/forum/el...ml#post1951644
 
  #15  
Old 03-30-12, 04:17 PM
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Originally Posted by ray2047 View Post
I've suggested a simple easy solution already. Can you explain why you need to make it so complicated?

http://www.doityourself.com/forum/el...ml#post1951644
yeah, maybe that would be simplest way
 
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