24 or more A550 cameras to fire at once

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24 or more A550 cameras to fire at once
« on: 14 / April / 2016, 17:19:10 »
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Hello
I've been reading for days and days and although there's a ton and a half of info to sift through I can't seem to get a clear idea of how to fire all my 24 powershot A550 cameras simultaneously.
James Gentles informed me they no longer produce the gentStereo which looked promising but this is 24 cams not 2 stereo. I know its covered here I just cant find a definitive thread to follow.
I have 24 cams on 8 tripods and I need a usb firing system.
Currently I use rechargeable batteries so I have to remove and recharge them so it's no big deal at this point to remove the cards and transfer the files that way for now at least, I just need the triggering procedure and a source for any hardware needed,
Thanks for you time

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Offline reyalp

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Re: 24 or more A550 cameras to fire at once
« Reply #1 on: 14 / April / 2016, 20:59:40 »
If you haven't seen it already, you might find some useful resources on this page http://chdk.wikia.com/wiki/Multiple_Cameras_using_CHDK

You can trigger all your cameras using the USB Remote, which just requires that you be able to control the USB +5v on all cameras.
Don't forget what the H stands for.

Re: 24 or more A550 cameras to fire at once
« Reply #2 on: 14 / April / 2016, 21:17:36 »
James Gentles informed me they no longer produce the gentStereo which looked promising but this is 24 cams not 2 stereo.
That's interesting.  Over the course of several emails some time ago, I tried to convince James that a hardware solution for hooking up multiple cameras (power, USB communications and CHDK USB remote shoot) was a good business opportunity.  He and his silent partner seemed to express interest but it never went any farther.

In your case, you are mostly looking at either a big wiring job (24 USB connectors with the +5 pin and GND pins wired in parallel to a switch and 5V power source) or an interesting job of connecting a whole bunch of USB hubs with some way to switch the power off.  Working in your favor with the direct USB connector project is your use of batteries in each camera - you don't have to puzzle out the grounding of many cheap Chinese camera power supplies.

I can draw you a simple wiring diagram if it would help.

Ported :   A1200    SD940   G10    Powershot N    G16

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Offline reyalp

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Re: 24 or more A550 cameras to fire at once
« Reply #3 on: 14 / April / 2016, 21:38:32 »
or an interesting job of connecting a whole bunch of USB hubs with some way to switch the power off.
A lazy person who didn't want to do any soldering could probably use one powered USB hub with a switch (e.g. http://www.newegg.com/Product/Product.aspx?Item=9SIA4GW1EB5439&cm_re=usb_powered_hub-_-9SIA4GW1EB5439-_-Product) plus a handful of unpowered ones.

I wouldn't trust this much for actual USB data transfer, but for just turning power on and off, it seems like it ought to work.
Don't forget what the H stands for.


Re: 24 or more A550 cameras to fire at once
« Reply #4 on: 14 / April / 2016, 21:42:04 »
Thank you yes a diagram would help. I am inclined to use usb hubs and power it with a usb charger that has an off on switch
Here is some of Mr. Gentles response
"This refers to a product called gentSTEREO which is mentioned on a few forums, unfortunately the product was discontinued last year and we cannot produce any more (some critical parts are no long stocked (even for repairs now!) The parts are printed circuit boards that we designed and we would need to buy an uneconomical quantity.
 Regards
James"

24 or more A550 cameras to fire at once
« Reply #5 on: 14 / April / 2016, 21:44:28 »
A lazy person who didn't want to do any soldering could probably use one powered USB hub with a switch.
I think that should work.  But the problem with most powered USB hubs is that they will pass power even when their power supply is turned off.  And the camera USB port draws so little power that it may or may not still work.  So much testing is required I fear

Edit : this comment assumed you also are using the hubs to connect your PC to the cameras.  If you eliminate that, it should work as described.  The "sync" might not be great but it should be adequate.
« Last Edit: 14 / April / 2016, 21:56:33 by waterwingz »
Ported :   A1200    SD940   G10    Powershot N    G16

Re: 24 or more A550 cameras to fire at once
« Reply #6 on: 15 / April / 2016, 01:30:45 »
You can trigger all your cameras using the USB Remote, which just requires that you be able to control the USB +5v on all cameras.
If you are interested in some additional a450 and a460 cameras (aprox 60++).
see Zcream's post here https://chdk.setepontos.com/index.php?topic=4103.msg117749#msg117749

Some "Design" stuff to consider about USB-2 Hubs:-

a/  Maximum USB-2 cable length is about 5 meters (without "Active" Repeaters.)
b/  "Active" Repeaters will initially start in USB-1.1 Mode and try to switch to USB-2 Mode.
c/  7 Port USB-2 Hubs are actually just two 4 port Hubs but connected  in series. !!
d/  10 Port USB-2 Hubs are actually just a 4 port Hubs and a additional (??) Hub connected  in series. !!
e/  "Powered" USB-2 Hubs also have "Additional Capacitive" Power By-pass Filters. !!
f/   "Powered" USB-2 Hubs also have a "Current Limiting" Resistor for short circuit protection. !!

So, All this will have some  "Sync" effect when the triggering your a550 Cameras via "Powered Hubs" ....

Also the a550 cameras are only USB-1, and they don't have much spare RAM. When compared to newer
cameras.

To improve the a550 "Sync" it's possible to remove the above components.
But you will still need to have + 5 volt power for the USB-2 Controller Chips in the Hub's.
The External +5 volt Connector is "Directly But via a Switch" connected to the "Output" end of the Hub's
internal current limiting resistor. The USB-2 Hub controller chip is powered via the Computers
USB Cable i.e the "Input" end of the current limiting resistor.

As the a550 and other Canon P&S cameras only require less than 2 Milli-amps the Hubs "Power Switch"
won't do very much. The +5 volts, will just continued, to be supplied via the Input USB Computer Cable.

Note #1 That TWO completely different things need to Happen. When you attempt to
"Sync" the a550 cameras via the USB-2 Hubs.

a/ To "Fire" the Camera's via the (Hardware) Hubs need's to be done in Parallel.
b/ To "Read" the Camera's SD-Card via the  (Hardware) Hubs need's to be done in Series.

The Operating System, when "Reading", will only connect to One camera at a time via the USB-2 Hub's.
The OS will just "Ignore" the remaining a550 Cameras if +5v is still supplied to the camera.
CHDK, then, just turns off each camera's internal "USB Switch" via the USB-1 or 2 and CHDK software. 

Note #2 it's also possible to attempt to "Sync" via the CHDK Software.

Note #3 Breeze Systems (Commercial) "PS-Remote" might also work with the a550 Camera See:-
              http://www.breezesys.com/PSRemote/index.htm
 However there will be about 0.6 sec "Sync" firing delay between each camera.
So "PS-Remote" is not very useful when shooting subjects that could move during the exposure's.

H-H

Edit #1 Re:- "...To improve the a550 "Sync" it's possible to remove the above (HUB) components..."

There are two ways to Hack the Hubs:-

A/ By "physically" removing some (HUB) components.
B/ By "electrically" removing or "isolating" the (HUB) USB +5 volts directly at the USB Sockets.

The +5 volts "Power" socket is then directly connected to ALL the USB Sockets +5 volts pins.

Edit #2 Another way is just to Hack the Output-USB Cables and isolate the +5 volts wires.
this is what z-cream did, So I now have 100 "Hacked" Original Canon Cables that were once
selling on ebay for about $Us5.00 each. -=(???)=-

« Last Edit: 15 / April / 2016, 21:27:21 by Hardware_Hacker »

Re: 24 or more A550 cameras to fire at once
« Reply #7 on: 15 / April / 2016, 06:52:02 »

It was mentioned in the Forum some years ago that a professional user of SDM did a commercial shoot of a golf pro practicing his swing.

24 cameras were mounted on three tripods and powered from a single lead-acid battery. Another small battery and switch were connected to a 24-way hub. It was as simple as that, no laptop using CHDK PTP was required.

For some shots the shooting delay was gradually increased from camera-to-camera, the result being that as the viewpoint swings in an arc around the golfer his club swing changes position.

The SDM author mentioned in the post that the images were manually transferred to the PC, not fun but not particularly tedious either.



Re: 24 or more A550 cameras to fire at once
« Reply #8 on: 15 / April / 2016, 09:59:24 »
Thanks for the input one and all
I now have a much better feel for this aspect of the project
Bruce

Re: 24 or more A550 cameras to fire at once
« Reply #9 on: 15 / April / 2016, 13:05:07 »
The usb cable lengths I would be using far exceed the passive distances
My rig is circular with a minimum radius of 17 feet.
BUT i am not sending or collecting data, merely 5v on and off and as you say the amount of juice needed for shutter release only is trivial , maybe that distance is ok?.
Would rather avoid the active hub or repeater situation as you say those will negatively impact sync
The cameras are in transit and I have ordered the enelope aa pro to power them and at the moment looking into deals on hubs and usb cables to order later today

-On another matter my understanding is that chdk will reside on the sdhc cards (4gb ordered earlier today) and no pc will be needed - am I right?
thks

 

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