Building a mult-camera rig - page 2 - Hotwire! Hardware Mods, Accessories and Insights - CHDK Forum

Building a mult-camera rig

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I think I've seen that one before somewhere ..

Quote
2. Decided to go we with option #3 (Remote USB & CHDK PTP )
Sounds safe.  You can always try the wifi options at a later date once you have all the rest sorted out.

Quote
Attach my design drawing (I would appreciate your opinion )
I'm not sure how much latency/delay there will be between all those relays switching the 5V to the USB ports?

As the ports really do not draw any appreciable current,  you might consider having all the plugs switched with a single relay - or at least multiple contacts on a multi-pole relay.

Unless you plan to encorporate a programmable delay between when each relay opens.  If so, you can do that with the CHDK Remote software by changing the sync delay.

Ported :   A1200    SD940   G10    Powershot N    G16

Re:- "more drawings"

"I'm not sure how much latency/delay there will be between all those relays switching the 5V to the USB ports?"

"Attach my design drawing (I would appreciate your opinion )"

Attached;- Multi-Camera_Array_Concept_[Write].png

The [Simplified] Parallel Write Concept for Read_Write - Decode Matrix 2.
The Logic Gates switch at a very high speed.

H-H

Continued
« Last Edit: 12 / June / 2014, 05:18:39 by Hardware_Hacker »

Re:- "more drawings"
"I'm not sure how much latency/delay there will be between all those relays switching the 5V to the USB ports?"
"Attach my design drawing (I would appreciate your opinion )"

Attached Multi-Camera_Array_Concept-[Read].png

The [linear and Simplified] ] Serial Reading Logic for "Read_Write - Decode Matrix 3"

The Cameras in the Array will "Auto Connect" in a sequence from Cam-#01 to Cam-#24,
But only one at a time.

Continued

H-H
« Last Edit: 12 / June / 2014, 05:17:15 by Hardware_Hacker »

"more drawing"
"I'm not sure how much latency/delay there will be between all those relays switching the 5V to the USB ports?"
"Attach my design drawing (I would appreciate your opinion )"

Continued

Attached [Re:- NO mechanical Relays]:-

No_Relays + Danger.png
NO_Relays_X.png

H-H
« Last Edit: 12 / June / 2014, 05:17:54 by Hardware_Hacker »


H_H, thank for the time & effort , still it is hard to understand :(

Although , I think I got your idea , please check the new circuit (instead of  relay board ), and advice me


Although , I think I got your idea , please check the new circuit (instead of  relay board ), and advice me
I don't think this buys you anything over just wiring all the 5V pins on the USB plug in parrallel.
Ported :   A1200    SD940   G10    Powershot N    G16

H_H, thank for the time & effort , still it is hard to understand :(

Although , I think I got your idea , please check the new circuit (instead of  relay board ), and advice me

Edit #1 Post Deleted, see post #17.
« Last Edit: 12 / June / 2014, 23:45:22 by Hardware_Hacker »

...., still it is hard to understand :
( Although , I think I got your idea , please check the new circuit (instead of  relay board ), and advice me

The [Simplified] Parallel Write Concept for Read_Write - Decode Matrix 2.
The Logic Gates switch at a very high speed.

"...I think I got your idea..." There are numerous ways a Multi-Cam rig can be controlled,
as this is basically an experimental concept/subject it is best to start with a least three
similar cameras and build simple test/rigs/prototypes for controlling the cameras.

This is what I have been doing, but my rig is designed to be much more "Modular" and
is not just a simple "Inwardly Pointing Camera Array".

For example, my "Mini_windows 8v1 PE O/S", will Load the "Boot.wim", Boot, and Run "ChdkPtp" in 2Gig of Ram,
From Win-Dos_8v1 with No Cd-Rom, No Start, No Metro-GUI, No Desktop, No File-Explorer, etc, etc.
So my Cheap and Small Laptop is a major part of a portable camera control system and rig.

Please Note that:-

Multi-Camera_Array_Concept_[Write].png was "Over Simplified"
.... as I was still thinking of the "Original Posts" whereby the USB-2
+5v pin was multiplexed to achieve multiple "USB Functions".

So back to Building a mult-camera rig
[was: Re:] and the Battery third (temp) terminal as multipurpose analogue input.

The Battery third terminal(s) is NOW used for the "Parallel" write/shoot camera input,
this input is NOT a differential input and is subject to noise pickup. But has the advantage
over USB-2 that the precise switching points are now very well defined. The Disadvantage is
a possible unknown sync delay.

When, one of cameras in the array, USB-2 +5v pin's is a Hi that camera will "Auto Connect" and
a "Serial" read/download is then possible. When USB-2 +5v pin's are Lo "Parallel" write/shoot
is enabled via the Battery(s) third terminal, "Common", analogue input(s).

To minimize the "Common Mode" noise pick-up on the "Common", analogue input(s) they can
use a co-ax cable from camera to camera, as shown, in Multi-Camera_Array_Concept_[Write].png

Also rather than sending a Digital "Voltage Sync Pulse" a "Current Sync Pulse" could be used instead.
The Camera far end termination [Network at Cam-#24] remains and a Camera near end termination [Network at Cam-#01] provides the required Voltage to Current pulse conversion.

Adding an additional 24 suppression Ferrites wont change the Co-Ax Cable and the current pulse as it appears as additional common mode noise rejection. i.e as Differential CMR.

Connections to Cam-#02 to Cam-#23 are via Co-Ax "T" connectors [example; SMA type] these cameras
see the sync pulse as a "Voltage Sync Pulse" this also includes Cam-01 and Cam-24.

Edit #2 Re:- WW's post #10 and novsela post #14
[/quote]
"....you might consider having all the plugs switched with a single relay - or at least multiple contacts on a multi-pole relay...."
[/quote]

This alternative to post #17 would be better done by an additional 24 HS Cmos gates or 24 High speed Opto Switches but still synced in parallel using the the Battery third (input) terminal.

Edit #3
An advanced version of post #17 would be to have the sync pulse, AC coupled, and to use a simple form
of "Ternary Encoding", using this scheme the Battery third terminal  Analogue Input is pre biased to a
Digital 0 at a nominal "Zero" +2.5 volts, then, a nominal +v/Hi and -v/Lo sync voltage/current is required
to sync the cameras, this scheme has much better noise rejection at the cost of more CHDK complexity.
This is in some ways similar to the existing CHDK - Remote Pulse Width encoding  schemes.

H-H

Edit #1 [Deleted]

« Last Edit: 13 / June / 2014, 01:11:49 by Hardware_Hacker »


Continued
One carefully thought out and edited post (and not one edited long after the original post) might be easier for us to follow ?
« Last Edit: 12 / June / 2014, 21:47:02 by waterwingz »
Ported :   A1200    SD940   G10    Powershot N    G16

Sorry for the mix up, in the previous drawing I connected by mistake the remote shoot power to the Battery .


I am attaching the latest version for Multi camera rig using USB Remote with CHDK PTP for multi camera rig


waterwingz - Please confirm "HW - SW Design V2.png"
Hardware_Hacker - Please confirm "USB Remote with CHDK PTP for multi camera rig  V2.pdf"

Thx :)

 

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