I like photography, and as geek a like to take “tech” photographs. High Speed Photography is one of those. A classic is water balloon exploding, but to freeze the moment when the balloon is exploding we need to understand the timing. All action happen in, lets say, 5mS. Very little time. But the main problem is when to shoot. Yes, you can do it manually trying many times, until you get the shot. Or you can do it right. A typical DSLR camera has a delay of ~100mS from the time you press the shutter (or remote shutter). So if we detect the balloon exploding and we send a signal to the camera shutter we will take a shoot of… nothing, we’ll miss the action for 95mS. So we have to use another technique: we will arrange everything in a dark room, we open the shutter (bulb mode), and when the balloon explodes we… well, some electronic device, fires the flash. A flash has nearly no delay and a duration of (depend of the power) ~0.1mS. It’s perfect!
We juts need some way to detect the balloon exploding and fire the flash. First I use a mic with an amplifier + a comparator.
And worked very well… but the flash fires when the action started, and I want to see what happen after. So I made a “delayer” with a PIC microprocessor in order to add a variable delay to the signal.
Sorry, I don’t have the schematics, I made it on the fly. But it’s very simple.
And was amazing!… I could get the exact moment I wanted.
More pictures here
And a picture of my bathroom (sorry) with all the setup. You can see the camera, the flash, the “delayer” and the mic (near to the balloon).