Recently, I've been using the Arduino to do some high-speed camera strobe triggering to accomplish stop-motion photography. Standard project done a thousand times- electret microphone, sound triggered. Typically, when using an Airsoft gun to shoot Christmas Tree bulbs, I use a 75ms delay from sense of the sound to firing of the strobe. The shutter is otherwise open.
The problem I'm running into is that the flash duration from my Interfit 150 studio head is way too long, even dialed back to minimum power. I'm getting flash durations of around 1/2000sec, where I'd like to be dealing with flash durations more in the range of 1/10,000 or less, to freeze as much motion as possible. As the flash duration IS the exposure time, 1/2000 sec is pretty slow when dealing with exploding glass.
So, I've done research and have thought of several solutions (short of glacialwanderer's spark-gap flash).
One is modification of a cheapo flash (like from a cheapo disposable camera). Inherently the overall power is lower of course, but it's typically a shorter duration flash to get that. As the trigger on these is high voltage, I'll probably use a 5v relay (they have 20msec switch time, which I can take off the strobe delay). I don't think I've got a transistor or SCR handy in that HV range, but a PCB-mount mini-relay should suffice.
In reading, one method is to replace the flash storage capacitor with a smaller one, resulting in lower energy, which is shorter flash. I may try this if i have a cap that's in the right range. If I don't, I was thinking about being a real idiot:
In the flash, an oscillator is fed through a transformer to charge a HV cap. Instead of reducing the cap, couldn't I instead place a bleeder resistor across the cap, and feed the transformer PWM? In this way I could control the charge level of the storage capacitor by PWM. Sounds good on paper until I start working the WATTAGE of that bleeder, I'd need a very high wattage (high voltage at high current storage) resistor, wouldn't I?
Last but not least, also looking at trying to use a couple of power led's I've got around.. led's react in the nanosecond range... I know the actual power is low compared to xenon- orders of magnitude, in fact- but proximity to the subject (inches) may compensate for that- nothing to lose in trying....