A6500 High Speed Capture With Flash - Issue With Delayed Flash (Need Help W/Program)

I put together a Circuit with Arduino and parts (copied a RIT project).

Want to capture balloon ripping apart as the dart impacts and creates a popping sound.

This is done in darkness with the shutter held open and the exposure from the flash.

The problem is that the flash is delayed. I need help adjusting the flash timing.

Script is done with Arduino IDE.

I don't have an experience with those balloon experiments but i would expect that when the sound of balloon explosion register the microphone it is too late to start any action (even without any other delay).

I tried google and sound + ballon was used when the content of balloon was water and few images what i found was everytime with already destroied balloon.

If you want to catch collapsing ballon i would expect that you have not primarily problem with delay in program but registering of sound. So for example that microphone has to be "on balloon" (as close as possible) or other mechanism has to be used.

Luisifer wrote:

If you want to catch collapsing ballon i would expect that you have not primarily problem with delay in program but registering of sound. So for example that microphone has to be "on balloon" (as close as possible) or other mechanism has to be used.

Thanks for comment and suggestion.  Yes, I agree and will try closer.

boblug wrote:

I would comment out the led lines. Not sure why they are needed.

Also move the digitalwrite(flash, low) before the loop and add a copy of this line before the end of the loop.

Move the digitalwrite(soundsensor, high) before the loop also

in the if statement comment out the first delay and change seconf delay to 50 milliseconds.

This should remove a little of the time delay and keep your sensor as close as possible.

I'm not sure exactly what the deal is with that "give flash time to settle down" delay is.

I'm also not entirely familiar with the Arduino environment/IDE - all of my work with Atmel AVR controllers has been via avr-gcc.

If I were doing this:

I'd choose an AVR that had analog comparator interrupts available - http://www.avr-tutorials.com/comparator/utilizing-avr-analog-comparator-interrupt-feature

This will let you immediately change the output pin state when the interrupt executes.

A "typical" trick I use with most AVR projects is to have a timer/counter intterupt configured to trigger periodically, often at 1 kHz.  This is used for less time-sensitive housekeeping - for example, set a variable inside your analog capture interrupt to indicate that a trigger event started.  In the timer/counter interrupt - count a certain number of ticks of said interrupt once the "event started" flag was set before unsetting the trigger output pin.

TBD how to handle the "lock out another flash for X seconds" situation - multiple possibilities here.

mawyatt2002 wrote:

Hi William,

The sound is created by the air escaping from the ballon, thus the ballon has already burst by the time the sound trigger is detected as previously mentioned.

You can solve this problem with another sensor that is triggered slightly before the ballon burst, maybe an optical trigger that responds to the falling dart before it punctures the ballon.

Another simpler solution which requires no additional triggers and should work with your code, is simply place another ballon well above this ballon and allow the dart to puncture the top ballon first then fall thru and puncture this ballon. You can estimate the required delay time between the ballon bursts with simple physics of falling objects.

Hope this helps,

Best,

Thanks so much for the suggestions.  I really like the idea of a target before the balloon (I will try several things).  Although I also have a super simple solution that has moderate success (see below):

what about setting your camera on a timer and right before the timer is up throw the dart. If your having flash issues go to camera settings and set the flash to go off seconds before the shutter

depending on camera you can create a time lapse video and pull a 4k 6mp image from the video. You should be able to pull the exact frame you want, not exactly how you creatively want to capture your image but it should work if all else fails.

Detecting the POP! is doomed to failure without knowing the specifics of the audio sensor. It may be protected from low frequency sounds ( like any proper mic would be ) or the op-amp may be inverting the signal, so that you miss the leading pressure wave.

Use a solenoid ( electromagnet ) to suspend the dart, when the solenoid de-energizes, under the control of your arduino, the dart falls per Newton, and probably some other people.

Even better than a dart would be a pin, much more dramatic and nobody will guess you used a magnetic release. They will think you have the patience of Job to drop that pin perfectly vertically.  Electromagnetic release is also useful for many other very wonderful setups, so worth building it.