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Low end, how to work with flicker LEDs on 1.5v

Discussion in 'LEDs and Optoelectronics' started by the13bats, May 30, 2018.

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  1. the13bats

    the13bats

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    Aug 11, 2015
    okay, im a low level hobbiest and enjoy playing with led lighting,

    I want to be clued in about the flickering candle look leds powered by 1.5 volt, ( technically less than 1.5 ) rechargeable cells,

    Heres some background, i buy those cheap solar garden led lights, most are one or two white leds powered by a single rechargeable aa or aaa cell,

    horror tool fright sells ones with a color changing led and i just picked up one at the dollar store a lantern style that has a fake candle and the led flickers on a single aa then recharged during sunlight,

    I take a flicker blub out of a small tea light that also flickers, it has of course a 3v button cell,

    i replace the white or color changing led in other solar lamps and while they do work, they light up all night and charge during the day they dont flicker,
    I want my flicker dagnabit,

    So since i cant find a flicker led that is 1.5 volt i look at the basic boards in these lights, most only have a couple similar looking parts, nothing very high tech looking, but that must be the key,

    So, why will the single aa led solar lantern flicker but the others i cobble up only light up no flicker,

    Please dim, no pun intended, it down where i can grasp it,

    Many thanks
    b
     
    Last edited: May 30, 2018
  2. kellys_eye

    kellys_eye

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    Jun 25, 2010
    The 'flicker' LEDs have a built in chip to do the flickering. It's supposed to be (anecdotally) a sound generating chip that's playing 'happy birthday' - see if you can follow the sequence whilst watching the light!

    If you run the LEDs at the wrong voltage you can destroy the controllers - and the LEDs

    Same with the multi-colour LEDs, they have circuitry built-in too.
     
  3. the13bats

    the13bats

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    Aug 11, 2015

    Thanks for the trivia and reply but it really didnt touch down on my questions in my op,
    And no, my flicker leds are not destroyed, yet anyway,
     
  4. KJ6EAD

    KJ6EAD

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    Aug 13, 2011
    You want something designed to run on 3V to run on 1.5V but you want the answer to be simple. Okay, no, it won't. Different circuit; different parameters.

    Here's the complete, non-simplified answer:
    Specialty LEDs with on board circuitry to control flicker may require either a fixed voltage or current limiting in the manner typical of ordinary LEDs while color changing LEDs require a voltage source in a specified range to operate correctly.

    https://cdn.evilmadscientist.com/catalog/components/semi/LED/datasheets/BL-L314UxW-B-S3.pdf

    http://cdn.sparkfun.com/datasheets/Components/LED/changingLED.pdf
     
    Last edited: May 30, 2018
  5. the13bats

    the13bats

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    Aug 11, 2015
    Okay, i think i got long winded convoluted my question,

    Ill start from scratch and work up,

    How do solar rechargable led lights work when all they supply is 1.5 v with one aaa or aa battery?
     
  6. KJ6EAD

    KJ6EAD

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    Aug 13, 2011
    They don't supply 1.5V to the LEDs. They have a boost circuit that raises the voltage to what the LEDs need. Often, the battery has a nominal voltage less than 1.5 since they are typically NiMh or NiCd technology.
     
  7. the13bats

    the13bats

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    Aug 11, 2015
    Here we go, see it was simply, and this boost circuit will vary depending which type led the solar lamp has,
    Would you happen to know the type i need to run a flicker led...

    Many thanks
    b
     
  8. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
    The body circuit also typically applies a pulsing DC to the LED.

    If this is a single colour LED then it doesn't matter because you can't see the flickering (it happens too fast).

    For Multicolor or flickering LEDs, the pulsing DC probably resets the chip inside so you just get the first colour or brightness level.

    My first try would be to get a solar lantern with a Multicolor led, and replace it with a flickering led.

    If that didn't work (and you may have already tried this) then my conclusion would be that the flickering led is more sensitive to variations in voltage. I might then try modifications to the circuit to reduce this variation.
     
  9. the13bats

    the13bats

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    Aug 11, 2015
    Steve, ty, you were the cat i was hoping to hear from,

    Yes, i tried the board from a color change lamp and no flicker solid on,
    Is there a simple novice way to smooth out the variations in voltage?

    There isnt a cheap source that i can find, might be out there, but i need that same board that is in the flicker lantern, they arent cheap but cool looking, to me,

    I saw some larger solar flicker tea lights on ebay but the solar cell has the faux flame in its center,
    I might order a few see if they will work for my projects,
     
  10. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
    Try placing a capacitor in parallel with the LED. I'd grab something like 47uF at 10V. Beware that the capacitor is polarised and you need to connect it the right way around.
     
  11. 73's de Edd

    73's de Edd

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    Aug 21, 2015
  12. the13bats

    the13bats

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    Aug 11, 2015
    Edd,
    Just me, one bat, its a dark campy play on 12 monkeys,

    Steve pretty much jumped right on what i was asking about,

    I do understand the flicker led has a built in chip,
    I also know leds have a voltage range they like to be fed,

    Im getting ready to test the cap idea steve gave me to see if that gets mine flickering,

    Will update in a few...
     
  13. Audioguru

    Audioguru

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    Sep 24, 2016
    A solar garden light has a voltage boost circuit that pulses a white or single color LED at a frequency high enough that looks steady. But when the solar garden light uses a color changing LED then the pulsing cannot be used so the circuit has a series Schottky diode feeding a filter capacitor to supply smooth DC. If you simply connect a capacitor parallel with the LED then the boost circuit stops. Of course a smoothing capacitor will not cause flickering, the LED must have a flickering circuit in it or on the circuit board.

    You cannot cause a colors changing LED to flicker but you can use a flickering LED in a tea light to cause a single color LED in a solar garden light to flicker if it is in series with the flickering LED, I do not know if a flickering LED needs smooth DC or if it works with the pulsing DC.
     
  14. the13bats

    the13bats

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    Aug 11, 2015
    Audioguru,

    Heres what i have tried and the results,
    I didnt get to try Steve's cap idea as i dont have that value on hand.
    Are you saying it wont work?

    I wasnt desiring to flicker a ccled.

    I took a garden light that had a color changing led, i removed the ccled and replaced it with a flickering led from a tea light, this led has the flicker circuit built it, its the only led there,
    It stays steady on no flicker that i desire,

    I tried a garden light that had two white leds in parallel so i removed both replacing them with one flicker led and again it comes on but doesnt flicker,

    So thats where i came here to get clued in what i need to make the flicker led flicker on these old solar garden lights,

    If im gasping this correcly my guess is my garden lights produce pluse and my flicker led requires smooth,

    How does the store bought flicker solar garden light work?

    I am aware that if a flicker led is in series with a solid color led they both will flicker from the circuit in the flicker one, but are you saying if i do this on one of these failed attempts it will then make the two leds flicker and solve my problem?


    I guess my easiest cheapest way out is buy a few solar flicker tea lights off ebay and extend the led to the project i desire.

    Basically this is for wanting the faux flame flicker effect in old real lanterns and other things of that nature i like to decorate my yard with.
     
  15. Audioguru

    Audioguru

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    Sep 24, 2016
    I have never seen a flickering solar garden light.

    Adding a capacitor to a solar garden light stops the voltage booster so it will not work. Instead you must add a series Schottky diode to the capacitor and LED in parallel like is used in a colors changing solar garden light. We do not know the capacity of the capacitor that is needed for a flickering LED. Most of my colors changing solar garden lights have a capacitor that is only 0.1uF (100nF marked "104"). 47uF or more might be needed for a flickering LED.

    A colors changing LED has a chip inside it that times the colors so flickering it will not cause the colors to change, it will always turn on to the first color.

    We are assuming that the flickering LED has a chip inside it to make it flicker. The flickering circuit might be inside the tea light instead.
     
  16. the13bats

    the13bats

    23
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    Aug 11, 2015
    Audioguru,



    No, im not assuming my tea light flicker leds have the built in flicker circuit,

    I know the do because,

    I can see the chip,

    All that is in the flicker tea light is a 3v button cell and plastic piece that makes a low end switch, making one lead touch button cell other lead stays touching other side of button cell.

    I can take that led run it on one AA no light,
    Run two AA in series 3v hook that to that led it flickers, so it must contain the circuit.

    Later today i will take pix of the solar flickering garden light, ( to me any out door solar light is a garden light )

    Its a metal lantern style about 10" tall fake candle inside, flicker led as candle flame, runs on one AA i can recall whats on the board so i will take picrures of that too,
    But i assure you it flickers really nicely,
    All kinds are all over ebay starting with ones that look like a large tea light with solar cell built around the led on top,

    I will also take a pic of the ccled board as i only recall it having a resistor and a 4 pole little black chip, ( see i am a novice lol )
     
  17. Audioguru

    Audioguru

    3,130
    697
    Sep 24, 2016
    Since the flickering LED has a circuit inside it and since it flickers when powered with enough DC battery voltage then the solar flickering light must have a boost IC, a boost inductor and it has a series Schottky diode feeding the LED with a capacitor in parallel to smooth the boost pulses.
    Here is a schematic of a solar garden light driving a colors changing LED:
     

    Attached Files:

  18. the13bats

    the13bats

    23
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    Aug 11, 2015
    Well i opened the garden lamp with flicker light,
    This site doesnt seem to host pix,

    The board has one led,
    One resistor
    And one 4 legged ic with number YX806 5h688
    I couldnt find anything on google but might not be looking correctly.....my guess its the key to what i desire to do...
     
  19. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
    It most certainly does.

    The "upload a file" option while you're replying will do the trick, and if you click on "more options..." There's even more stuff for you.
     
  20. Audioguru

    Audioguru

    3,130
    697
    Sep 24, 2016
    Your YX806 IC is on my list and shows an "L" which is an inductor that looks like a resistor. The IC operates its voltage boosting at 350-420KHz. In Chinese it is called "candle flash" which might mean flickering.
     

    Attached Files:

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