4 ms·

I was today years old when I learned that the frequency of a flicker candle flame is ~9.9Hz :-)

JKCalhoun 1y ago
That is awesome. And I am so sad an individual that my first thought was of a software plug-in that would use this frequency to generate realistic candle-flicker effects.
- alnwlsn 1y ago
  To continue this tangent, legend has it that some of those battery powered tea candle lights actually reuse the chip from cheap music playing trinkets. If you replace the yellow LED with a speaker, you might hear beepy christmas music or happy birthday. I've never found one myself (most of them have a better candle simulation chip than that), but they are apparently out there.
  - cpldcpu 1y ago
    This was 10-15 years ago. In between they used dedicated ASICS: https://cpldcpu.com/2013/12/08/hacking-a-candleflicker-led/ https://cpldcpu.com/2013/12/08/hacking-a-candleflicker-led/ And more recently simply microcontrollers: https://cpldcpu.com/2024/01/14/revisiting-candle-flicker-leds-now-with-integrated-timer/ https://cpldcpu.com/2024/01/14/revisiting-candle-flicker-led...
    - kridsdale1 1y ago
      What a testament to the might of the global electronic supply chain that entire computers are cheap enough to be in disposable candles. Single use Vape-pens too. Some of those have displays and Bluetooth. Insane.
      - epcoa 1y ago
        Just to offer an alternate perspective. While technically a PIC12 is a computer since it has I/O, tiny storage, a PC and an ALU - it’s hard to even think of it in the same category as what most think of as a computer. IMHO the takeaway is more what the bare minimum it takes to be a computer, which isn’t much. (In other terms, a PIC does not meet the DOOM threshold). PICs are so old and rudimentary that they started out as peripheral controllers for “real” computers in the 70s. It turns out you can do some useful embedded stuff with a basic chip, but even the newest of these are on 30 year old semiconductor tech at this point. That may sound jaded, on the other hand I do find mass production of modern level integration and speeds to still be marvelous. And as an EE, the “white” LED in the candle is more interesting than the uC!
      - masfuerte 1y ago
        In strings of programmable LED lights every single LED is actually an LED combined with a computer. This allows the LEDs to be addressed individually without loads of wires.
        progbits 1y ago
        Computer is overselling it a bit. It's a fixed logic latch+shifter. Basically each LED takes first few bytes for itself and shifts out the rest down the chain. Still awesome this is small and cheap enough to put into individual lights of course.
      - firefax 1y ago
        single use vapes should be outlawed imho -- it's so wasteful to include both the cart and the "pen" (power delivery) in one package to be thrown away.
    - alnwlsn 1y ago
      Wow, I'm clearly behind on my flickering candle LED technology knowledge. Thanks!
    - bob1029 1y ago
      https://en.wikipedia.org/wiki/Chua%27s_circuit https://en.wikipedia.org/wiki/Chua%27s_circuit
      - cpldcpu 1y ago
        Chaotic circuits are neat, but they are actually not random (their output distribution is not uniform or gaussian). And candles are not random either :) btw, slightley related: https://cpldcpu.com/2020/06/15/building-a-chaotic-oscillator/ https://cpldcpu.com/2020/06/15/building-a-chaotic-oscillator...
        bob1029 1y ago
        > their output distribution is not uniform or gaussian https://www.worldscientific.com/worldscibooks/10.1142/7200#t=aboutBook https://www.worldscientific.com/worldscibooks/10.1142/7200#t... > "More in details, Ando and Graziani demonstrated that the Chua's circuit can be used to generate either a gaussian or a uniform white noise. To do this, they investigate the statistical and spectral characteristics of the signals generated by a Chua's circuit with respect to different values of the parameters α and β. They then applied the x^2 method to determine which set of parameters leads to a signal having the statistical and spectral characteristics more similar to those of either a Gaussian or uniform noise. By using this method, a signal with a Gaussian-like distribution is obtained with a confidence of 95% for this set of parameters: ..." They've got charts of the probability density functions for each that seem reasonable to me.
        cpldcpu 1y ago
        Nice, I was not aware of that! Quite interesting. Thank you for the source. It seems to be a corner case. As I learned to know them, chaotic circuits have unpredictable cyclic behavior. Chua's circuit typically follows an oscillatory behavior with a double attractor. If true randomness is the goal, it is much easier to use other sources of randomness like avalanche transistors, jitter of ring-oscillators in the analog domain or LFSRs if you are in the digital domain.
        1y ago
  - kridsdale1 1y ago
    Related to this, I once read that the reason nearly every car alarm in the 1990-2010 approx era had the same pattern of awful sound patterns was that they all simply used the same off the shelf sound IC which was produced in such quantities as to make any custom option untenable. The “car alarm sequence” of 10s patterns was just the self-test demo program for the sound chip.
    - throwup238 1y ago
      I believe they were the HK628 and UM3561 chips which were launched in the 1980s for toys. You can actually hear that alarm sound on some toys from that decade. They were simple chips that stored 8-16 preprogrammed sounds and the urban legend is that the car companies just kept the alarm demo sound (I think there were two different ones). The chips ended up everywhere: toys, care, appliances, industrial machinery, etc.
  - jjice 1y ago
    Very neat! I've also seen that some will use Linear Feedback Shift Registers [0] for the candle effect, or maybe that's the same thing you're talking about. Edit: I see the article in a sibling comment makes note of this too. [0] https://en.wikipedia.org/wiki/Linear-feedback_shift_register https://en.wikipedia.org/wiki/Linear-feedback_shift_register
Mistletoe 1y ago
I never thought it would be as regular as that graph and thought it was random. The world around us is so fascinating.
thesnide 1y ago
and is it slower or faster on the moon? oh wait...
- beardyw 1y ago
  Assuming you had enough oxygen to waste on this I don't think it says if it would be faster or slower. I wonder which it would be?
twic 1y ago
The frequency of the flicker of this particular candle flame is ~9.9 Hz. From TFA: > the dimensions of the fuel source are defined by the size (diameter) of the candles and possibly their proximity Candles vary in size, so other candles may have different frequencies.

That is awesome. And I am so sad an individual that my first thought was of a software plug-in that would use this frequency to generate realistic candle-flicker effects.

alnwlsn 1y ago
To continue this tangent, legend has it that some of those battery powered tea candle lights actually reuse the chip from cheap music playing trinkets. If you replace the yellow LED with a speaker, you might hear beepy christmas music or happy birthday. I've never found one myself (most of them have a better candle simulation chip than that), but they are apparently out there.
- cpldcpu 1y ago
  This was 10-15 years ago. In between they used dedicated ASICS: https://cpldcpu.com/2013/12/08/hacking-a-candleflicker-led/ https://cpldcpu.com/2013/12/08/hacking-a-candleflicker-led/ And more recently simply microcontrollers: https://cpldcpu.com/2024/01/14/revisiting-candle-flicker-leds-now-with-integrated-timer/ https://cpldcpu.com/2024/01/14/revisiting-candle-flicker-led...
  - kridsdale1 1y ago
    What a testament to the might of the global electronic supply chain that entire computers are cheap enough to be in disposable candles. Single use Vape-pens too. Some of those have displays and Bluetooth. Insane.
    - epcoa 1y ago
      Just to offer an alternate perspective. While technically a PIC12 is a computer since it has I/O, tiny storage, a PC and an ALU - it’s hard to even think of it in the same category as what most think of as a computer. IMHO the takeaway is more what the bare minimum it takes to be a computer, which isn’t much. (In other terms, a PIC does not meet the DOOM threshold). PICs are so old and rudimentary that they started out as peripheral controllers for “real” computers in the 70s. It turns out you can do some useful embedded stuff with a basic chip, but even the newest of these are on 30 year old semiconductor tech at this point. That may sound jaded, on the other hand I do find mass production of modern level integration and speeds to still be marvelous. And as an EE, the “white” LED in the candle is more interesting than the uC!
    - masfuerte 1y ago
      In strings of programmable LED lights every single LED is actually an LED combined with a computer. This allows the LEDs to be addressed individually without loads of wires.
      - progbits 1y ago
        Computer is overselling it a bit. It's a fixed logic latch+shifter. Basically each LED takes first few bytes for itself and shifts out the rest down the chain. Still awesome this is small and cheap enough to put into individual lights of course.
    - firefax 1y ago
      single use vapes should be outlawed imho -- it's so wasteful to include both the cart and the "pen" (power delivery) in one package to be thrown away.
  - alnwlsn 1y ago
    Wow, I'm clearly behind on my flickering candle LED technology knowledge. Thanks!
  - bob1029 1y ago
    https://en.wikipedia.org/wiki/Chua%27s_circuit https://en.wikipedia.org/wiki/Chua%27s_circuit
    - cpldcpu 1y ago
      Chaotic circuits are neat, but they are actually not random (their output distribution is not uniform or gaussian). And candles are not random either :) btw, slightley related: https://cpldcpu.com/2020/06/15/building-a-chaotic-oscillator/ https://cpldcpu.com/2020/06/15/building-a-chaotic-oscillator...
      - bob1029 1y ago
        > their output distribution is not uniform or gaussian https://www.worldscientific.com/worldscibooks/10.1142/7200#t=aboutBook https://www.worldscientific.com/worldscibooks/10.1142/7200#t... > "More in details, Ando and Graziani demonstrated that the Chua's circuit can be used to generate either a gaussian or a uniform white noise. To do this, they investigate the statistical and spectral characteristics of the signals generated by a Chua's circuit with respect to different values of the parameters α and β. They then applied the x^2 method to determine which set of parameters leads to a signal having the statistical and spectral characteristics more similar to those of either a Gaussian or uniform noise. By using this method, a signal with a Gaussian-like distribution is obtained with a confidence of 95% for this set of parameters: ..." They've got charts of the probability density functions for each that seem reasonable to me.
        cpldcpu 1y ago
        Nice, I was not aware of that! Quite interesting. Thank you for the source. It seems to be a corner case. As I learned to know them, chaotic circuits have unpredictable cyclic behavior. Chua's circuit typically follows an oscillatory behavior with a double attractor. If true randomness is the goal, it is much easier to use other sources of randomness like avalanche transistors, jitter of ring-oscillators in the analog domain or LFSRs if you are in the digital domain.
      - 1y ago
- kridsdale1 1y ago
  Related to this, I once read that the reason nearly every car alarm in the 1990-2010 approx era had the same pattern of awful sound patterns was that they all simply used the same off the shelf sound IC which was produced in such quantities as to make any custom option untenable. The “car alarm sequence” of 10s patterns was just the self-test demo program for the sound chip.
  - throwup238 1y ago
    I believe they were the HK628 and UM3561 chips which were launched in the 1980s for toys. You can actually hear that alarm sound on some toys from that decade. They were simple chips that stored 8-16 preprogrammed sounds and the urban legend is that the car companies just kept the alarm demo sound (I think there were two different ones). The chips ended up everywhere: toys, care, appliances, industrial machinery, etc.
- jjice 1y ago
  Very neat! I've also seen that some will use Linear Feedback Shift Registers [0] for the candle effect, or maybe that's the same thing you're talking about. Edit: I see the article in a sibling comment makes note of this too. [0] https://en.wikipedia.org/wiki/Linear-feedback_shift_register https://en.wikipedia.org/wiki/Linear-feedback_shift_register

Mistletoe 1y ago

I never thought it would be as regular as that graph and thought it was random. The world around us is so fascinating.

thesnide 1y ago

and is it slower or faster on the moon? oh wait...

beardyw 1y ago
Assuming you had enough oxygen to waste on this I don't think it says if it would be faster or slower. I wonder which it would be?

twic 1y ago

The frequency of the flicker of this particular candle flame is ~9.9 Hz. From TFA: > the dimensions of the fuel source are defined by the size (diameter) of the candles and possibly their proximity Candles vary in size, so other candles may have different frequencies.