LED Night Lights

Discussion in 'The Projects Forum' started by Jackal10, Feb 15, 2009.

  1. Jackal10

    Thread Starter Member

    Feb 15, 2009
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    I am trying to make some night hunting lights, I am considering purchasing these, lights and driver. My question is do I need to heat sink each individul one. I currently plan to epoxy each one in an outside (swival) socket. Any help would be greatly appreciated.
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
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    The info sheet offers the line "reduced sinking requirements". It's going to dissipate over 2 watts of heat, so mounting it on a sink will be necessary.
     
  3. Jackal10

    Thread Starter Member

    Feb 15, 2009
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    Thanks! One more question if you will. If I mount it to the heat sink, and then incapsulate in the epoxy will it be ok, or do I need to get free air to it?
     
  4. Wendy

    Moderator

    Mar 24, 2008
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    I have seen designs that were encapsulated and heat sinked, they never worked too well, since epoxy is generally a lousy thermal conductor. Encapsulate the side the part is mounted, but leave metal free air standing perhaps?
     
  5. iONic

    AAC Fanatic!

    Nov 16, 2007
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    Is the red LED an example or is it what you want. Is there a reason for the red light as apposed to, let's say, something in the green spectrum. This spectrum is more effective for human night vision.

    If you have proper heat sinking, that is, with the heat sink exposed to the exposed air you should be OK with covering the electric components such as the LED circuitry, excluding the LED lens itself. If the heat sink is vastly larger than required then complete enclosure might be OK too, but that just unnecessary bulk and weight. If the heat sink is aluminum then exposure to air and moisture will not be an issue.
     
    Last edited: Feb 15, 2009
  6. Jackal10

    Thread Starter Member

    Feb 15, 2009
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    Well it is hunting season again and I am back on my light project. I am asking for some help to design a photo control circuit (on in the dark, off during the day). I need a low energy consumption control as I will be using a small 12 volt battery that is solar charged during the day. Any Ideas would be greatly appreciated.
     
  7. Audioguru

    New Member

    Dec 20, 2007
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    The datasheet for the LEDs is preliminary and leaves you guessing about the size of a heatsink. It says for you to measure the temperature with an IR thermometer then select a heatsink so that they are not too hot.

    The LEDs have a fairly high current so the solar panel will be pretty big and expensive and the battery will not be small.
     
  8. Jackal10

    Thread Starter Member

    Feb 15, 2009
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    This is a schematic I drew from a photocell controller that doesn't work anymore. Can someone explain to me what is going on in this circuit so I can troubleshoot it. It is a dimmable (external) led driver controlled through a photocell, I can't get a good look at the resistor but I think it is a 39K, the little contact is a Kest KS2E-M-DC5, capacitors are 3300uf. I drew it by looking at it and finding the symbols so if something looks crazy I might have to take a closer look. Thanks!
     
  9. Wendy

    Moderator

    Mar 24, 2008
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    [​IMG]

    I have to be honest, I can't read this schematic. There are two parts I have problems understanding, the square +5V and -5V coming out of it, and part labeled K52E-M-OC5. I assume it is an IC, but the part number is a total mystery.
     
  10. Chris15

    Active Member

    Apr 15, 2009
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    Hey Jack
    i also do hunting and wanted a night vision scope IR light, is this what you are talking about
     
  11. Jackal10

    Thread Starter Member

    Feb 15, 2009
    17
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    Chris

    No this is for some LED lights to put under my feeder to see hogs at night operated by photocell and hopefully using the same battery as the motor in the feeder. I am a bow hunter so I am fairly close.
     
  12. Jackal10

    Thread Starter Member

    Feb 15, 2009
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    First, thanks for looking at it! the square is the driver, linked on the first thread, it is one that is dimmable, the second is a relay, which I think the coil is operated by the photoresistor,transistor side of schamitic. I figured it would be hard to read as I am not electronic savy. I have attached the data sheet of the kest contact which seems to me fails to say if they or normally open or closed. I am also trying to figure out exactly what/how the crtl and ref. does on the driver.
     
  13. Wendy

    Moderator

    Mar 24, 2008
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    What is the power supply voltage, I'm assuming it is DC?
     
  14. Jackal10

    Thread Starter Member

    Feb 15, 2009
    17
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    voltage is 12v DC,

    here is my theory, photoresitor let enough power through to operate transistor switch that engages the coil on the contactor? What I don't understand is how the dimmer portion works on the driver, I think it is just being used as an on off switch?
     
  15. Wendy

    Moderator

    Mar 24, 2008
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    I'll get back with you, as it is my birthday, and I plan on doing some other things today. When I get a chance I'm going to redraw that schematic. How a schematic is presented often determines it's readability.
     
  16. Jackal10

    Thread Starter Member

    Feb 15, 2009
    17
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    Thank you, Happy Birthday to ya, it is also my 3rd daughters birthday today.
     
  17. Wendy

    Moderator

    Mar 24, 2008
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    OK, I hadn't forgotten you. I took an educated guess as to the relay, I'm betting the contacts are marked on the case, so they didn't feel the need to put it in the data sheet.

    [​IMG]

    There are several things going on here that need fixed. You didn't record the part values, so I will make more assumetions.

    The way you're using the transistor is totally off. It needs to have the emitter collector reversed. You need to have a variable resistor for the resistor in series with the photocell, though you could get lucky and the one you're using may work just fine. Instead of a capacitor across the coil of the relay you need a diode, this keeps the high voltage kick from the relay from blowing out your transistor.

    I'll redraw this schematic again with the corrections in a bit. Again, I don't really know how the relay is wired, but it is a good guess.

    I have also never used a Puck Buck, so I don't have a clue yet if there is a problem there. It looks good from what little I know.
     
    Last edited: Sep 27, 2009
  18. Jackal10

    Thread Starter Member

    Feb 15, 2009
    17
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    There is a great possibility that I have it drawn worng, as I stated I am not very electronic savy, the photo resistor, transistor, and resistor are incapsulated in a clear acrylic and a little hard to see.
     
  19. Wendy

    Moderator

    Mar 24, 2008
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    Did you make them?

    Looking at the datasheet for the puckbuck I would do it differently anyhow. Instead of using the remote on/off, just turn the power directly on/off at the power leads. Can you get the driver (puckbuck) to light the LED with just the 12V and it?
     
  20. Jackal10

    Thread Starter Member

    Feb 15, 2009
    17
    0
    No I did not make it, it was purchased by a friend and quit working, I was trying to make it work again so I could use them on my lights. I have a puck buck that only has power in and led out, with no control/refrence, on and off does not matter to me as long as I can get them on at dark and off during the day with minimum amount of power consumption. Thanks Again Bill For your help. I appreciate it!

    Also the puck buck with the control/ref comes on as long as there is nothing tied to the +5v (open)
     
    Last edited: Sep 30, 2009
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