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anyone know the maximum flash rate of an LED? Answered

I need to pulse a light very quickly (think really fast strobe) and by very quickly, I mean at about 350Hz. I need the light to be on for ~1ms or less at a time (maximum acceptable length is 1.517ms) I'd like to operate at 5v or less, and have a nice wide dispersion pattern... Is this possible with a standard LED? With this sort of PWM, will I even see the light? Is there a better alternative to an LED? help will be greatly appreciated

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karanbhandarkar (author)2012-06-21

on the similar lines, can someone help me with what LED is used for a flash in current iPhones and Androids(on the lines of galaxy). Can those LEDs me modulated at really high speeds again so that the flashing isn't detected by the human eye. Say around 1KHz

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gschoppe (author)karanbhandarkar2012-06-21

I looked into it... unfortunately, the android SDK only lets you access the flash through an SDK function that has significant lag... so no strobelight flash

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karanbhandarkar (author)gschoppe2012-06-21

Thank you for your reply. So there's no possible way to use a timer for it and set it at a very high frequency either?

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user

Did you ever discover the max refresh rate of an iPhone LED? Can't seem to find it without building my own prototype.

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user

If you mean of the screen, it's 60Hz.

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gschoppe (author)2007-05-20

nicely done... I really didn't expect anyone to get that.... i'm utterly amazed at your speedy thought

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adam 101 (author)gschoppe2012-01-26

did you ever make this project?

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gschoppe (author)adam 1012012-01-26

I did. You can find the instructable I made on my page, for a visual / audio tuning trainer

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VIRON (author)2007-05-20

Anything that blinks that fast... you can't tell it's blinking, but solid state video cameras may help see the blinking. But you can use a 350hz LED strobe as timing light, for making very fast motors look stopped. LED's can blink over a million times a second.

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westfw (author)2007-05-20

What kind of LED? I think ALMOST all LEDs will have no problem with 350Hz and 1.5ms pulses; that's well withing the range used by standard multiplexed 7-segment displays. The exception MIGHT be white LEDs, and the danger would probably be that the phosphor wouldn't turn off fast enough to yield distinct pulses, not that you wouldn't see light. I'm pretty sure that LEDs are used in fiber optic data transcievers for (eg) optical ethernet at frequencies of 10MHz plus. It's when you get to multiple GHz that lasers replace LEDs. (of course, these aren't your standard indicator style LEDs, but it still says good things about the limits of the technology.)

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gschoppe (author)westfw2007-05-20

ah, now, Lemonie, if I told you that I would spoil the fun... my only hint to you is... what inverts its output every 1.517ms? Or, to be more precise, what inverts its output every 1.517ms or 2.025ms or 2.551ms or 3.406ms or 4.505ms or 6.068ms depending on setting? westfw, thanks a bunch.

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gschoppe (author)2007-05-20

The other consideration is, at 5v, 350ma I'll need the light to be bright enough to illuminate objects nearby (less than 2 feet away) in a lighted indoor setting... the illumination needs to be bright enough to get a strobe effect to the naked eye. any suggestions for the LED?

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lemonie (author)2007-05-20

What are you aiming to build? L

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