To capture an instant on film or sensor with a camera, you usually need a fast shutter. But alternately a flash can be triggered with the scene in the dark and the shutter wide open. It’s this latter technique which PetaPixel are looking at courtesy of the high-speed class at Rochester Institute of Technology. They’re using a cheap sound sensor module and an Arduino to catch instantaneous photographs, with students caught in the act of popping balloons.
The goal here was to keep things as simple as possible. All you’ll need in addition to the Arduino (or really, any modern microcontroller) is the sound sensor — which are often sold as “microphone shields.” To trigger the flash while still providing electrical isolation is a reed relay. The write-up notes that higher performance systems would be better off with an optoisolator, but this provides a low-cost alternative to get started with.
We rather like the technique, and perhaps it’s a thing to try at a future hacker camp. Unsurprisingly it’s not the first flash trigger for water balloons we’ve seen.
Could have used a 555.
wow, electronics are so abstracted now, lets overbuild because someone cant build with $4 in parts,555, mic,resister, cap.
Who knows maybe people use an ESP with embeded os because they cant blink and led and read an adc at at same time lol
The article is a good write up if you are a photographer. I have been meaning to try something similar to this for a while as I get better at flash photography. They explain all the lights they use and their purpose.
For the Arduino, probably wasn’t a bad choice for an amateur project like this. As they used it to help measure signals out, and even tweak delays between hearing the pop and triggering to get the right amount of burst ballon. This could be useful for quick accurate changes in a fast pace of a studio without playing with too much test gear.
Design from smarter everyday did something similar years ago photographing ballers fired into an apple I believe. Surprised what you can see with a short flash duration!
Kinda bugs me how an Arduino and module are used but then they cheap out on the switch. However, lets keep in mind the target audience are photographers. Its always cool to see non electronics people do this kind of stuff. And the photos look damn cool.
Trying not to be negative here so kudos for the lighting info and the pics are good.
But ‘keeping it as simple as possible’ by using thousands of lines of code (if we include the libraries), a PC, IDE and $20 of parts (including a reed relay that’s almost definitely not suited for the task) for a job that’s been done to death thousands of times in all sorts of electronics magazines and books since the 70s (and almost definitely earlier too) with dirt cheap stuff like the 555, op-amps, logic ICs etc???
Definitely not the first to do this, but nevertheless fun :-) Even the photography website Petapixel had this years before: https://petapixel.com/2017/05/10/build-simple-sound-trigger-high-speed-photos-arduino/
The most prominent “trigger your photo/flash with an Arduino” I remember was the Photoduino from ~10 years ago: https://kalanda.github.io/photoduino/ The flexibility justified the use of a microcontroller over a 555, too ;-)
Are optoisolators that much more expensive than reed relays? As I always harvest my opto’s from broken SMPS’s I really wouldn’t know.