It's been a long time since anyone posted a DIY shutter tester. I found this one, another using the our famous photo diode and resistor but using Sound Fordge as the timing program instead of Cool Edit which is no longer available. THis one also has nice diagrams explaining the use of the device.
I actually built this one, or another one very similar. It works for me. However, buying Sound Forge just for this is an overkill and rather (for me at least) expensive. So I use an open-source and free program called Audacity. It can be downloaded here: http://audacity.sourceforge.net/
