Developer-friendly / experimental branch (dataghost)

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39

Re: Developer-friendly / experimental branch (dataghost)

« Reply #100 on: 09 / July / 2008, 15:03:55 »

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A few thoughts:-
Coriolis acceleration. The earth association in this context seems incorrect and some notes which appear to be relevant are at www.eng.auburn.edu/~ramada/mems/schedule.htm especially week 14 Notes. There also some useful notes on WIKI Coriolis. Google 'beam accelerometers'
Photo interpretation (S3is RAW)
If the photo showing the accelerometer is enlarged (500-1000% with Photozoom trial?) it seems the 'paired copper bits' (beams) suggest (to me) a piezoelectric beam measuring x, y motion about the optic axis by generating and measuring the Coriolis acceleration. I haven't worked out a convincing explanation of the parallel 'copper bits' but the literature lays emphasis on the drive and driven beams having similar natural frequencies. The pin joining the four beams is the means by which vibration is transferred (coupled).
Canon IS technology not much detail discovered except the IS lens is driven in x and y directions no rotation.

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Bg~

27

Re: Developer-friendly / experimental branch (dataghost)

« Reply #101 on: 09 / July / 2008, 20:14:56 »

Re: S3 pictures
The devices in the S3 pictures are definitely piezo gyroscopes. See NEC TOKIN Piezoelectric Devices for a somewhat generic explanation on how that particular type works. I think the basic gist is that piezoelectric materials generate electricity when they are deformed (in addition to deforming when an electric current is applied), the electrodes on those rods measure the change electricity generated due to rotation. The 'pin' is the actual measurement device, and the electrodes you see are just supporting the beam so it is free to vibrate. The IS system is driven by the two gyros sensing pitch and yaw motion of the camera which move the IS lens vertically and horizontally to compensate.

Canon BCTV Lenses: What is Optical Image Stabilizer?

« Last Edit: 09 / July / 2008, 20:17:40 by Bg~ »

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LjL

266
A720IS

Re: Developer-friendly / experimental branch (dataghost)

« Reply #102 on: 10 / July / 2008, 07:03:26 »

I guess this helps explaining the sensitivity to magnets.

What I'd like the most to have explained, though (or at least given a working transformation to correct for it, but knowing the cause wouldn't hurt) is why 0 degrees is not the same as 180 for the sensor that's supposed to be on the vertical axis (and the same can be said for 90 and 270)...

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toby

46

Re: Developer-friendly / experimental branch (dataghost)

« Reply #103 on: 27 / November / 2008, 14:48:58 »

Omg!
I just found this topic and saw these videos.
Ithought "holy sh**".
That orientation-view is awesome, and so is your work. *thumbs up*
This looks like a horizon from a flightinstrument. How about creating a flightsimulation? *ggg*

What knowledge did u had to use to create the orientaton-view???

Greetz Toby

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tgran

12
A570IS (101A)

Re: Developer-friendly / experimental branch (dataghost)

« Reply #104 on: 05 / March / 2009, 16:04:04 »

Am I missing something? It seems that the axis A and B outputs could be used as a camera trigger.

« Last Edit: 10 / April / 2009, 07:15:20 by tgran »

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PhyrePhoX

2254
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Re: Developer-friendly / experimental branch (dataghost)

« Reply #105 on: 14 / April / 2009, 19:39:29 »

yes, they could be

one day the stuff from dataghost findings will end up in trunk, that is my prediction. but it needs time and dedication, as this is pure asm magic

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Re: Developer-friendly / experimental branch (dataghost)

« Reply #106 on: 15 / April / 2009, 16:28:12 »

Quote from: tgran on 05 / March / 2009, 16:04:04

Am I missing something? It seems that the axis A and B outputs could be used as a camera trigger.

...a kind of "real" camera motion detection ?!

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tgran

12
A570IS (101A)

Re: Developer-friendly / experimental branch (dataghost)

« Reply #107 on: 18 / April / 2009, 13:46:07 »

I can think of a few uses (I do KAP!), but a basic one would be:

1) Push shutter button
2) wait for minimum in angular velocity along the two axis (won't correct for rotation about optical axis)
3) take picture

There's an iphone application like this that allows people to take better pictures in low light without a tripod. That one uses accelerometers though.

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jphphotography

25

Re: Developer-friendly / experimental branch (dataghost)

« Reply #108 on: 09 / September / 2009, 04:54:08 »

Hey everybody I've just been scrolling through the pages here, this thread was referenced in another I was reading about disabling the camera's pre-flash.

I think this feature would be valuable to anyone wanting to use off camera lighting, there is a growing community of "strobists" out there (if you don't know what strobist is check out strobist.com its all about off-camera lighting)

Most of these "strobists" use flashes in manual mode, they just need a trigger flash to set them off. If the power could be controlled then all the better, probably wouldn't want it full strength so that it doesn't contaminate the shot but that could be worked around by obstructing the flash a little with kleenex or something to knock it down.

Anyway I just wanted to see what was up with this so please reply if you've got anything new.

Thanks!

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Microfunguy

4037

Re: Developer-friendly / experimental branch (dataghost)

« Reply #109 on: 09 / September / 2009, 05:16:53 »

Quote from: jphphotography on 09 / September / 2009, 04:54:08

Most of these "strobists" use flashes in manual mode, they just need a trigger flash to set them off.

Are you concerned about preflash because it will trigger simple slave flashes ?
You can buy slaves that only react to the main flash.
Alternatively, a simple circuit using just three components will trigger your external/studio flash after a preset delay after releasing the USB remote switch.

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