Does LED make for a good strobe? - Page 2

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Re: Does LED make for a good strobe?
On 17/06/13 09:35, Trevor Wilson wrote:

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http://www.ledsales.com.au/catalog/index.php?main_page=product_info&cPath14%8_188_221&products_id77%7
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Point taken about white LED persistence - good info.
Does it happen in the LED, or the human eye?
Those RGB LEDs are probably too big, but they look pretty nifty and I  
should buy one just to play with!


Re: Does LED make for a good strobe?

"Jordan"

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http://www.ledsales.com.au/catalog/index.php?main_page=product_info&cPath14%8_188_221&products_id77%7
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** Do you bother reading posts at all ?

 Try reading mine again pal, its number 2 in the thread.



...... Phil




Re: Does LED make for a good strobe?

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  Yes, silly me.

Re: Does LED make for a good strobe?
On 18/06/2013 9:16 AM, Jordan wrote:
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http://www.ledsales.com.au/catalog/index.php?main_page=product_info&cPath14%8_188_221&products_id77%7
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**As PA has already explained, the problem lies with the construction of  
all white LEDs. A white LED is actually a blue LED, with a fluorescent  
coating. The coating is the problem. It has a persistence.


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**You could consider a green LED, as they are not only available in in  
quite high outputs, but the human eye is highly sensitive to green.


--  
Trevor Wilson www.rageaudio.com.au

Re: Does LED make for a good strobe?
On 18/06/2013 12:50 PM, Trevor Wilson wrote:
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http://www.ledsales.com.au/catalog/index.php?main_page=product_info&cPath14%8_188_221&products_id77%7
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Why not a laser diode module with a diverging lens to give the size of  
spot needed.

Re: Does LED make for a good strobe?
On 18/06/13 21:12, keithr wrote:
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That's interesting, I didn't know these existed. Cheap too.


Re: Does LED make for a good strobe?
On 19/06/2013 12:05 PM, Jordan wrote:
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Some LD modules don't like to be turned on & off quickly - perhaps due  
to the integrated driver circuitry.

Also some LD modules are already strobing the LD, I think this is done  
as a cheap way of controlling LD power dissipation. I've got a couple  
where if you rapidly sweep the beam across a surface you can see the  
light o/p going on & off.


Re: Does LED make for a good strobe?


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Bare laser diodes aren't all that hard to find, one of the chips in a DVD  
laser is visible. If you can get hold of scrap point of sale equipment -  
most of the bar code readers use visible lasers.  


Re: Does LED make for a good strobe?

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lamps. These are very effective at "stopping dead" the
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Any chance with LEDs?

This project uses a white LED as a strobe, published in August & September 2008.
http://archive.siliconchip.com.au/cms/A_110798/article.html

SC did some testing of the 1W white Luxeon and a Cree XR-C .
The 10% to 90% full brightness measurement was 290nS, 90% to 10% was 360nS.
To get enough light though, they made the minimum strobe flash period 32uS.

BTW
Some people confuse the slow phosphor used in CRO tubes with white LEDs.
The phosphor used in most white LEDs does not phosphoresce but emits
light by scintillation, an effect that has virtually no light persistence, so
the speed
is mostly determined by the underlying blue LED.





Xenon are much brighter and faster and would be better in bright ambient light.





Re: Does LED make for a good strobe?
On 20/06/2013 11:43 PM, yaputya wrote:
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lamps. These are very effective at "stopping dead" the
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image. Any chance with LEDs?
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2008.
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the speed
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**You may be correct. Specs on Luxeon emitters seem to bear out the rise  
and fall times will be fast enough for most purposes.


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light.

**Certainly, but a 5 Watt LED would deliver plenty of light for anything  
but for use in direct sunlight. IOW: In a car engine bay, a white LED  
will easily be adequate.




--
Trevor Wilson www.rageaudio.com.au

Re: Does LED make for a good strobe?

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lamps. These are very effective at "stopping dead"  
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image. Any chance with LEDs?
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2008.
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the speed
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fall times will be fast enough for most purposes.

Here is the info from SC
http://imageshack.us/photo/my-images/834/upo8.jpg/


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light.
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for use in direct sunlight. IOW: In a car engine bay,  
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You still have to stretch the LED pulse out to get much light whereas the
Xenon flash is brighter at shorter pulse widths.
You can see the result in digital camera flash comparisons:
http://www.dpreview.com/forums/post/51353395

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