Building a mult-camera rig

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Building a mult-camera rig
« on: 08 / June / 2014, 17:45:07 »
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while following this thread I have found few more option / alternative to implement multi camera 360 deg, that I would like to share with you and get your opinion

1   Remote triggering via software with CHDK PTP
2.   Remote triggering via USB remote with wifi / eyeFi SD card for downloading image to PC
3.     Remote triggering via USB remote with CHDK PTP (control & data transfer)

Since option 1 suffer from sync issues I would like to start with option 2 and progress to option 3 (while having Battery temp trigger optionall )
 
Remote triggering via USB remote with wifi / eyeFi SD looks like simple solution since the donload image from cameras to pc is done via the eyeFi SD card.  for the remote USB triggerung i will need use simple electronic board with multiple output .

I would like to start with 24 cameras for the 360 rig (360/24 = 15 degree) and placed the camera in Vertical position in order to capture toll objects / people  , the rig diameter would be 3 meters.
(Till now, all the rigs I saw, the cameras were installed in horizontal position , why is that ? )

Therefor, downloading the images from the cameras to PC with WiFi wont take to much (wifi N is supported , and I might use two Access Points / dual radio AP for faster downloading)

important issue related to naming correctly the files, Is the option to set the file name (images) in the cameras ?instead of using the conventional naming ( I want to identify the camera according to file name, for example 1_xxxx-01.jpg -  meaning taken by camera no 1 , 5_xxxxx-01.jpg was taken by camera no 5)
Is it possible ?


As for the third option (Remote triggering via USB remote with CHDK PTP) , there is good information in in the following link - http://chdk.setepontos.com/index.php?topic=8769.msg107967#msg107967

Since the main issue with this option is to change mode between live (for USB Remote shutter trigger & sync) and playback (for downloading images) , few solutions were offered such has Hack USB hub (by Hardware_Hacker) ,custom code to mask USB remote in playback mode (http://chdk.setepontos.com/index.php?topic=8769.msg105488#msg105488) .

I would appreciate your opinion on the following drawing , where as remote trigger done under USB Remote via 8/16 port USB controlled relay (either USB or Virtual com)  and date via USB hub.

Can I used Karmaschinkens electrical design (made for temp trigger but might fits here ) to trigger via arduino (USB remote ) http://chdk.setepontos.com/index.php?topic=10385.msg109595#msg109595 

Regards

*

Offline reyalp

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Re: Building a mult-camera rig
« Reply #1 on: 08 / June / 2014, 18:56:24 »
Remote triggering via USB remote with wifi / eyeFi SD looks like simple solution since the donload image from cameras to pc is done via the eyeFi SD card.  for the remote USB triggerung i will need use simple electronic board with multiple output .
Note that you might be better off using one of the more hackable wifi SD cards than actual eye-fi.  See http://chdk.setepontos.com/index.php?topic=11262.0 and http://hackaday.com/2013/09/19/advanced-transcend-wifi-sd-hacking-custom-kernels-x-and-firefox/

Quote
Therefor, downloading the images from the cameras to PC with WiFi wont take to much (wifi N is supported , and I might use two Access Points / dual radio AP for faster downloading)
In my experience, a lot of consumer wifi equipment behaves badly with more than a few active devices. The actual wifi transmitters + antennas in the cards are also probably quite weak. So while it certainly might work OK, it would not be a surprise if running 24 of these things in the same room with 24 cameras and 24 power supplies ended up being problematic in some way.
Quote
important issue related to naming correctly the files, Is the option to set the file name (images) in the cameras ?instead of using the conventional naming ( I want to identify the camera according to file name, for example 1_xxxx-01.jpg -  meaning taken by camera no 1 , 5_xxxxx-01.jpg was taken by camera no 5)
Is it possible ?
Generally speaking, CHDK cannot control the name of the jpeg when they are being saved. CHDK scripts can rename files, but this can cause problems if you are doing it on files in the image directories. On some cameras, removing (or renaming, presumably) an image using CHDK will cause the camera to crash when you switch back to play mode. This mostly applies to recent cameras.
With a little hacking you could potentially use the filewrite hook to change the name the camera saves under (on ports that have filewrite implemented and fully working), but this could trigger the same issues as deleting/renaming.
Note the above only applies to jpeg. If you only work with DNG, then CHDK could easily be modified to save it under any name the OS allows.

All dryos cameras only support DOS 8.3 filenames, so your actually ability to name is limited.

An alternate approach would be to have each wifi card upload to a different directory, and then use some program on your PC to rename them appropriately, perhaps based on the time in the exif. It may also be possible to hack the card to do the naming for you.

You could also generate a log file along with your images and use that to rename them later.

edit to add another comment:
A number of people have successfully implemented your option #3, using either USB or battery temp triggering. So you know for certain that one is possible.
I believe people have also used #1 in situations where timing is not critical, but I'm not certain of the number of cameras.
You might be the first to attempt #2 if you go that route.

Also, I'm going to split this into a new thread, since it isn't really about the battery terminal hack.

« Last Edit: 08 / June / 2014, 19:09:43 by reyalp »
Don't forget what the H stands for.

I would appreciate your opinion on the following drawing , where as remote trigger done under USB Remote via 8/16 port USB controlled relay (either USB or Virtual com)  and date via USB hub.

I have modified your drawing and attached some extra files.

Some design Points to be considered:-

1/ USB-2 Cable lengths and noise pickup problems.

2/ USB +5v Decay Times. (try to minimise the decay time)

3/  "Serial" read/download logic for camera control, hardware, software and scripting.

4/  "Parallel" write/shoot logic for camera control, hardware, software and scripting.

5/  "Windows PC" for camera control, hardware, software and scripting

....... for more details, about "5/" and USB Device Class Drivers, see these posts:- #2 and #3
      http://chdk.setepontos.com/index.php?topic=11584.msg113421#msg113421

H-H

Continued Post #3
« Last Edit: 09 / June / 2014, 22:27:19 by Hardware_Hacker »

Continued from Post #2


thanks for the response although I didn't understand your drawing modification
I would appreciate if you explain it within less tech level :)


Regards


thanks for the response although I didn't understand your drawing modification
I would appreciate if you explain it within less tech level :)

".... implement multi camera 360 deg...." [Are there more design details available.]


Edit #4 This Multi-Cam protect may be helpful:-
             The $400, 96 Megapixel Panoramic [6] Camera
              “Very Small Array” (VSA) by Max Lyons, March 2014

http://www.tawbaware.com/vsa_camera_array.html
http://www.tawbaware.com/vsa_camera_array.pdf

"...Gotchas

There are a few “gotchas” working with a camera array. Just dealing with 6 of everything (6 cameras, 6 batteries, 6 memory cards, 6 chargers, etc.) turns out to be a minor logistical challenge..."

And Multi-Cam protect "'Image Management":-
             http://www.tawbaware.com/maxlyons/panostats.htm

~~~~~~~~~~~

Some design Points to be considered [But one at a time]:-

1/ USB-2 Cable lengths and noise pickup problems.

There is NO Cable length limit in regard to +5v "USB 2 Remote Switch" for
Shoot_Sync i.e ALL cameras in "Parallel", I think of this as a camera "Write" or Shoot.

There is an USB-2 cable length limit of 5 meters, Pc to USB-2 Hub. i.e for camera Reads/Downloads

There is an USB-2 cable length limit of 5 meters, USB-2 Hub to Camera. i.e camera for Reads/Downloads

We are just combining two very dissimilar technology's by "Hacking the USB-2 Hubs" or Hacking the
Canon Camera Mini-B USB cable and adding some sort of control switching system.

ALSO the longer ALL USB-2 and Control wiring is the greater the probability that Mains. Audio, Radio, TV,
Computer, Wi-Fi, etc Noise will affect the Camera Shoot_Sync. This is why USB-2 Canon Camera Mini-B
cables have a Ferrite Noise Suppression Fitted. This also enables the cameras cables to pass FCC regulations.

However the control switching system will act as a Ariel and pick up stray noise which will randomly affect
the Camera Shoot_Sync. see attached file.  Attack+Decay-USB 1.png  i.e. "USB Jitter"

There will also be some "USB Jitter" just due to difference's between USB Hot_Plug switch point's in canon cameras this will affect the multi-cam array Shoot_Sync.

Also See this post;- Re: Sync Multiple Cameras  Reply #4 on: 02 / March / 2012,
                      http://chdk.setepontos.com/index.php?topic=7758.msg82144#msg82144

Edit #1  The "USB 2 Remote Switch" is not a Differential cable system and is more likely to be affected
              by common mode noise pickup. i.e. for Shoot_Sync

Edit #2 The USB-2 cable uses twisted pairs to reduce induced noise. i.e. it is a Differential cable system.

See attached file; USB Cabling & Device Classes

H-H

to be continued....

Edit #3 May be this post has some effect when trying to sync multiple cameras:-
       CHDK task repeat interval timing precision  (USB Remote Pulse Accuracy)  02/June/2014
               http://chdk.setepontos.com/index.php?topic=11558.msg113210#msg113210
« Last Edit: 10 / June / 2014, 23:46:21 by Hardware_Hacker »

Edit #3 May be this post has some effect when trying to sync multiple cameras:-
       CHDK task repeat interval timing precision  (USB Remote Pulse Accuracy)  02/June/2014
               http://chdk.setepontos.com/index.php?topic=11558.msg113210#msg113210
Using the "sync" feature in the USB remote code removes any effect from the issues discussed in that post.
Ported :   A1200    SD940   G10    Powershot N    G16

Hi

Quick update

1.I succeed to build simple remote button/circuit and shoot from remote  :D
(Some relevant links:

2. Decided to go we with option #3 (Remote USB & CHDK PTP )
Attach my design drawing (I would appreciate your opinion )

Keep  you posted on future progress .....


more drawing

more drawing

 

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