non-candle-like flickering

Discussion in 'The Projects Forum' started by Deltafee, Nov 16, 2015.

  1. Deltafee

    Thread Starter New Member

    May 22, 2015
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    Hello, I have a need to make a led that flickers like a loose connection like in a horror film, I know I can program it with an ardunio but it seems like a waste of money to have an ardunio power just one light. Any ideas on how I can do this.
     
  2. Dodgydave

    Distinguished Member

    Jun 22, 2012
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    555 timers cascaded, or cmos logic gates,
     
  3. #12

    Expert

    Nov 30, 2010
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    Much like The Dodger...I'm thinking about a "count to 10" chip with a different value resistance on each output. Ten conditions, repeated, might not be detailed enough to satisfy your perception, but you can chain the chips to count to 20 or 30, etc.
     
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  4. Papabravo

    Expert

    Feb 24, 2006
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    I'm thinking LFSR (Linear Feedback Shift Register) with a slow clock and a long period.
     
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  5. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    I just made one. I used three triangle wave circuits at three different frequencies going into an adder circuit and comparitor. Quite random, as long as the frequencies are not multiples of each other.

    The pot lets the duty cycle to be adjusted.

     
    Last edited: Nov 16, 2015
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  6. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
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    Schematic?
     
  7. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    I see the intermittent light as mostly on with short erratic off periods as might be hard wired parallel load shift registers.
    I'll throw in a rough example to show the SR's. Would use a 555 as clock & SR's with a LED driver. Bottler Lightning 00000.png
     
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  8. ian field

    Distinguished Member

    Oct 27, 2012
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    It was probably Philips that discovered it - but it was found that driving a LED with a melody chip was more realistic candle effect than any circuit they could devise.
     
  9. GopherT

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    Nov 23, 2012
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    I used 3 of these triangle wave generator circuits set to 1, 2.7 and 4.7hz. Then added a 10k output resistor to each and feed into the (-) input of an op amp wired as a comparitor. The (+) input was a 10k pot to control the duty cycle.

    The triangle wave each needed half of a Quad amp. The comparitor used one quarter and a virtual ground at Vcc/2 used the last op amp.
     
  10. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    I was discussing this with an IP attorney.

    There are apparently all kinds of DIYers who have made patent applications for "realistic candle effect" and the patent office throws them out nearly immediately since there is little innovation, little value and most are in software that is not explained. Only a few have been patented and those are under challenge.
     
  11. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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    Google: welding arc LED circuit

    Ken
     
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  12. Bernard

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  13. ErnieM

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    Apr 24, 2011
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    I saw what looked to be a standard Edison base bulb, except it was dimmer since it was a LED inside. Screw it into an outlet and it gave the effect you desired.

    It was in a bin at Home Depot just before Halloween.
     
  14. k7elp60

    Senior Member

    Nov 4, 2008
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    Here is a circuit I developed a number of years ago. I put two blinking LED's in parallel, and in series with a yellow LED to make a flickering candle for a pumpkin. I found that the two blinking LED's needed black shrink tubing on them to prevent all the LED's from talking to each other FLICKERING CANDLE.jpg
     
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  15. RodneyB

    Active Member

    Apr 28, 2012
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    Is there no need for a series resistor?

    "LED's needed black shrink tubing on them to prevent all the LED's from talking to each other" How do you do this?
     
  16. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    I tried post 14, 2- white flashing LED's with 51 ohm in each anode, 200 ohm from cathodes to anode of bright white LED , cathode to ground. The periods of flashing LED's are just slightly different giving bright LED a semi random flash pattern as flashers go in & out of phase. Not spectacular. 12V.
    Note- Deltafee not seen since Tuesday.
     
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  17. k7elp60

    Senior Member

    Nov 4, 2008
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    Blinking LED's generally do not require a series resistor as they are normally rated at a maximum voltage because of the internal flashing circuit. LED's in certain circumstances will also detect light. In my circuit I cut two small lengths of shrink tubing, placed each one on the LED's, then used a heat gun to shrink the tubing. Shrink tubing is a common thing with electronics. It is different forms of tubing that
    when heated is shrinks in diameter. In my opinion the most common is one that shrinks to half it's diameter.
     
  18. RodneyB

    Active Member

    Apr 28, 2012
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    Thank you. So am I correct in assuming just the top of the led is out the heat shrink could you possibly post a picture
     
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