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[on:]

A very simple device but maybe someone is interested in this type of application. The idea is to shot cameras and flashes according to the inputs of different sensors.

A typical example will be wait until a wild animal crosses a IR barrier, then open the shutter of two cameras, then fire some flashes, then keep the shutters open for some minutes to capture ambient light. All that can be done with timers but the arduino allows much more flexibility without having to use a display since it can be connected to the computer.

First, I used the device to measure the time that a D200 needs to open the shutter.

http://frikosal.blogspot.com/2007/10/el-controlador-fr2-y-la-medida-del.html

Cameras and flashes are controlled with optocouplers.

Please don't be too hard with me, I knew about arduino about two-three weeks ago

[Reply #1 on:]

Nicely done!

Great way to measure delays, and fewer moving parts than the rotating disk method...

Would you mind sharing the schematics for the flash and camera control circuits?

[Reply #2 on:]

Nicely done!

Great way to measure delays, and fewer moving parts than the rotating disk method...

Would you mind sharing the schematics for the flash and camera control circuits?

Thanks, I'm glad that you like it.
I use optocouplers, I'll post the schematic as soon as I  finish it. Now I'm putting all the stuff inside a box.

What is the rotating disk method ?

[Reply #3 on:]

Used to measure time between two flashes. You have a disk with a radius line drawn (like the hand on a clock), rotating at a known speed. Take a picture exposed by the two flashes, the angle between the two lines on the disk will tell you how far the disk rotated between flashes.

Also used to measure exposure time or flash duration, if disk rotates fast enough to blur the line. The angle across which the line is blurred tells you how long the exposure or flash lasted.

Can't be used to measure shutter delay, I think, so your method is complementary, but also much easier to use!

The trick is knowing how fast the disk was rotating, but there are several tachometer designs for Arduino available on the web :-)

Alternatively, you could pulse some leds on the disk at known frequencies, which should give you lit dots while the flash was off, allowing you to calculate rotation speed, and then use a feature on the disk which is only visible during the flash for the rest...