LED High frequency Strobe

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Mechanic

Joined Mar 26, 2013
3
I am actually a mechanical engineering student and fairly new to circuits.

For my graduation project, I am building a test-setup in which we use a camera setup. To avoid having to use a high speed camera, we are looking into two exposures per frame to do PTV.
For that reason I looked into high power led-modules and am looking into a circuit that makes the LEDs flash at a clearly defined interval at a clearly defined speed.
Furthermore the circuit must accept trigger signals to be able to synchronise the camera. The camera sends out a pulse every time it takes a shot.

The pulses I need are of 0.1-1 ms and the times between the pulses in the same order, but always larger. I found the circuit posted below for the astable oscillator that puts out such a signal.

I found out the following project for driving high power LEDs http://forum.allaboutcircuits.com/showthread.php?t=32364.

I am now wondering whether I can actually switch the LEDs that quickly. And I furthermore wonder how should I incorporate the triggering?

 

GopherT

Joined Nov 23, 2012
8,009
LEDs can switch in the microsecond range. Check the DATASHEET of a specific LED. Higher power may be slower. Search LED above 75 mA on digikey.com.
 

ErnieM

Joined Apr 24, 2011
8,377
I once did an experiment to see how fast I could pulse a LED and still see it.

Damn, was so long ago I forgot how fast it was, but I believe it was under a microsecond, perhaps even 20 uS, and still quite visible to my eye from across the room.
 

Markd77

Joined Sep 7, 2009
2,806
0.1ms is no problem. The IR LED in a TV remote control runs at 36kHz and they are pretty much the same as visible LEDs.
If you only want to send two pulses, you might have to add a small delay at the start because otherwise they might have happened by the time the camera shutter is open.
 
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