The Arduino platform is frequently seen as the domain of hobbyists thanks to its low cost and open-hardware nature. That doesn't mean that it doesn't have a place on a professional's workbench, though, as Vela Labs' Matt Kane has deftly proven. Matt is working on building a high-speed camera flash, and uses an expensive photodetector connected to an even more expensive oscilloscope to do comparative testing. Realising that end-users wouldn't have easy access to nor budget for such equipment if they wanted to benchmark their existing flash units, Matt built a flash speed tester using an Arduino Leonardo, cheap photodiode and miscellaneous low-cost components totalling no more than around $3. Although Matt's project involves some workarounds for the relatively slow speed of the Arduino's Wiring library, the performance is high enough to give usable lag and pulse width figures for Xenon-based flashes - although not Matt's upcoming Vela One high-speed flash unit.
A photodetector will set you back $100 and upwards, and an oscilloscope is hundreds more. If you don’t have these already, this is much too expensive for most people if they just want to check their own flashes and compare them to others. I decided to build a budget version, based around an Arduino.