Checking to see if camera has finished taking photo

Hello,

I have a problem I've been thinking on for some time.

The problem:
I have mounted a Canon Eos 30D on a pan & tilt system for panorama footage.
I input degrees and time and such and the Arduino handles the rest.
The rig moves a certain degree before stopping and triggering the camera to take a photo.
This it repeats as long as I setup with the intention of sunrise to sunset.

Now the problem is that I must have automatic shutter speed on in the camera, because it has to be able to shoot in unknown light conditions during the time. This means between milliseconds to 30 seconds max.

Since the connection to the camera is, let's just say it, primitive (stereo-jack with only shutter and focus), the Arduino cannot know which shutter speed my camera has chosen. And I want to know it, roughly at least (to trim down wait time between photo and moving servos).

So my question is if anyone in here has a creative solution to this problem?

For example: My current idea is to attach a light sensor to the display on the back of the camera and, since it blackens during photo, just check when it gets back online. But that has its own problems.

Is there anyone with a better idea? Or more fun?

Accelerometer to detect the mirror “clack”?

TheMemberFormerlyKnownAsAWOL:
Accelerometer to detect the mirror "clack"?

Do you think it could work?
I already use a gyro to sense when the servos stop so it would be easy to move the location closer to the camera.
Yeah, I'm gonna try that.

If you’ve already got a gyro, see if that picks up a usable signal.

On a similar vein to checking the the screen, you could also check the view finder for light changes. Take a reading before the the shot, then read during and use those 2 reading to figure out when it had opened again.
You could make something that replaces the eyepiece rubber to make it easy to mount and exclude light that might come from anywhere other the the view finder.

What is the interval between pictures?

backwards:
You could make something that replaces the eyepiece rubber to make it easy to mount and exclude light that might come from anywhere other the the view finder.

That's actually a great idea. I checked the view finder and it should work perfectly.

JCA34F:
What is the interval between pictures?

For a 'dawn till dusk' session with 3 degrees per turn something like 20 minutes in between shots. Probably less degrees and more often.

TheMemberFormerlyKnownAsAWOL:
If you've already got a gyro, see if that picks up a usable signal.

Tried it. On the sensitivity i use for the servo it might detect it. Any more sensitive and it starts detecting every vibration. Don't think it will work with the slightest wind/traffic outside.

Could you perhaps just use the analog voltage from an LDR in one leg of a potential divider to get a rough measure of lighting conditions? And after some trial & error maybe you could map that to a shutter speed approximation?

Take picture, wait 1 min, move to new pos, wait 19 min, take picture...
Guess I don't see the need to move the camera immediately after taking the picture if the next picture won't be for several minutes. :confused: If you know the maximum time the shutter will be open is 30 seconds, then why not start a 60 sec timer at the same time the camera is triggered and hold the move until the timer has expired?

Terrypin:
Could you perhaps just use the analog voltage from an LDR in one leg of a potential divider to get a rough measure of lighting conditions? And after some trial & error maybe you could map that to a shutter speed approximation?

Hmm, that might actually work. I don't really know how a camera measures light now that I think about it. Anyway, as a rough estimation it would be good. Have to buy me a LDR and try.

JCA34F:
Take picture, wait 1 min, move to new pos, wait 19 min, take picture...
Guess I don't see the need to move the camera immediately after taking the picture if the next picture won't be for several minutes. :confused: If you know the maximum time the shutter will be open is 30 seconds, then why not start a 60 sec timer at the same time the camera is triggered and hold the move until the timer has expired?

Fair point. The basic 'try my new rig out' version I coded was just that. It took approx 2.5 hours to complete the full (half) circle, no more no less.
But A) that just isn't fun. :slight_smile:
B) It isn't versatile. Even though photographing over many hours is my main goal I also want to be able to take instant panoramas and everything between.
C) In the end I need to rely on batteries, and this is a part (not written yet) of preserving as much battery as I can by putting everything in sleep mode as soon as possible.