Quote Originally Posted by Steve Smith View Post
I did the same with mine. I have an IR photodiode mounted in a plastic plate and I place the camera with the back open onto this which places the diode at the film plane (or close enough). I use it on my kitchen worktop directly under a light fitting and I have found it works just as well with or without a lens fitted (35mm SLRs). It works fine with in shutter lenses too.

Mine has a 7 digit (7 segment LED) counter and a 100kHz oscilator which is gated by the photodiode. It gives the shutter time in milliseconds to the nearest one hundreth of a millisecond.

Okay, can you explain the last part? Or do you have a wiring diagram? I'm not a electronic engineer, I'm more into phusics, so I thought I'd use a simple circuit which I found on the net and just plug it in to the soundboard and use MATLAB to analyze (or audicity, but I feel matlab could integrate better..), but your versions sound much more accurate. I have had some doubt which gives the better readings, photodiods or phototransistors. But now it seems as IR is the way to go? Why would that be more accurate than for instance an ordinary laser pointer?

How would a circuit using a schmitt trigger look like? And how should I ground it? My original design was just a few diods and resistors in a battery box... As I said, I have only studied electronics on a high school level.

And btw, since I live in europe I don't have a radio shack close to me, the nearest electronic parts shop is an hour away. But that wasn't the issue anyway, it just would seem like a good idea to recycle, even if it's just a tiny tiny component, I feel bad everytime I pass the electronic junk pallet, there is so much stuff that could be used, instead it's gonna sit on some deposit, poisoning the earth. Well, when the metal prices are high enough, those circuit boards are gonna be hard currency, at least that's a comfort. Maybe I should start saving old 486 motherboards in my shed?