Setup for CHDK matrix bullet-time rig with Powershot A450 and A460 cameras - page 4 - Hotwire! Hardware Mods, Accessories and Insights - CHDK Forum

Setup for CHDK matrix bullet-time rig with Powershot A450 and A460 cameras

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MrSpoon

Re: DC Socket size on Canon Powershot models 1.1mm 1.3mm ??
« Reply #30 on: 23 / August / 2009, 20:12:31 »
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... if the resistors were biasing the transistor, they wouldn't be in series with the camera so they would have negligible current through them. How is a transistor a 'passives-only' solution??

Zener diodes wouldn't work, battery voltage falls over time. It also falls as current draw is increased. So you'd use the flash, voltage falls below the reverse breakdown voltage and oops, off goes the camera.

Really, this is basic electronics.

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Offline Anaglyphic

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Re: DC Socket size on Canon Powershot models 1.1mm 1.3mm ??
« Reply #31 on: 24 / August / 2009, 13:56:43 »
relax, killer. It's not a personal attack. I don't want to get into a "who memorized more of Horowitz and Hill's AoE in 9th grade" flexing contest, it won't help zcream in the least.

Battery voltage doesn't fall enough to matter, unless you exceed current. Since you'd never drain a 2Vx3 cell 6V SLA past 1.75V/per cell if you want to be able to recharge it repeatedly, you'll never drop below 5.25V.  So if you ran 3.3V zeners to clamp a 5.25-6.25V feed, you are right it is basic electronics... this in fact would work fine.

Oh! I get it. You were thinking using both the resistor divider AND the zener setup? Then your post would make sense. But why would you do that?
Since we cannot know all that there is to be known about anything,
 we ought to know a little about everything.
-- Blaise Pascal

Re: DC Socket size on Canon Powershot models 1.1mm 1.3mm ??
« Reply #32 on: 25 / August / 2009, 22:53:55 »
I guess I'm missing something here, but don't the cameras come with batteries and chargers?

It sounds like you are setting up a rig to do "Bullet time."   ???

If you are going to take sequential images, why worry about an external PS for 50 cameras with all the cabling and potential problems that could entail.

Buy a bunch of power strips and simply charge the camera's batteries the night before the shoot. They will probably last for a minimum of 100 exposures before needing recharging. That's 100 takes.

The more critical issue is controlling the timing of the sequential application of voltage to the USB ports. You'll need 50 discreet cables of limited length and a method to apply voltage to them individually at the proper time.

That's a lot more daunting task than simply powering the cameras IMHO.   :o
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Re: DC Socket size on Canon Powershot models 1.1mm 1.3mm ??
« Reply #33 on: 25 / August / 2009, 23:09:19 »
Hi cybercom. You are correct. Its a bullet time setup.
There is a problem with charging all batteries - we are talking abot a 100 batteries. Thats about 25-50 chargers. Simply dont have that many.
Also, I need one single cable then branching off to 50 cameras - I have already done it with the USB remote cables for the remote.
Also, if one battery fails the camera fails and the shoot is worthless. If I use a battery pack, there is a margin for error, its 2-3 batteries fail, there is still enough juice for powering the entire setup..
CHDK used for a Bullet-time sequence
Welcome to mishra.tv productions


Re: DC Socket size on Canon Powershot models 1.1mm 1.3mm ??
« Reply #34 on: 25 / August / 2009, 23:10:27 »
BTW my cameras were bought used off ebay. They do not come with chargers..I think its an optional accessory.
CHDK used for a Bullet-time sequence
Welcome to mishra.tv productions

Re: DC Socket size on Canon Powershot models 1.1mm 1.3mm ??
« Reply #35 on: 26 / August / 2009, 05:48:17 »
The more critical issue is controlling the timing of the sequential application of voltage to the USB ports.

Just set suitable delays in the Synch menu, slightly different for each camera.
It can be done with great precision.

Re: DC Socket size on Canon Powershot models 1.1mm 1.3mm ??
« Reply #36 on: 26 / August / 2009, 05:52:07 »
I need one single cable then branching off to 50 cameras

I am currently working with someone who is developing a commercial device to do that (and trigger external flash and shoot synchronised time-lapse).

He reads this forum and may even see this message.

Re: DC Socket size on Canon Powershot models 1.1mm 1.3mm ??
« Reply #37 on: 26 / August / 2009, 05:55:23 »
Exactly. The standard remote script. With a N*40ms delay, N=0,1,2...50
The more critical issue is controlling the timing of the sequential application of voltage to the USB ports.

Just set suitable delays in the Synch menu, slightly different for each camera.
It can be done with great precision.
CHDK used for a Bullet-time sequence
Welcome to mishra.tv productions


Re: DC Socket size on Canon Powershot models 1.1mm 1.3mm ??
« Reply #38 on: 26 / August / 2009, 05:57:00 »
The simplest way would be to have 1 cable with 5.5mm connectors on it..Just connect the standard dc cable to trigger a camera when you want to..

I might just solder it for the moment.
I need one single cable then branching off to 50 cameras

I am currently working with someone who is developing a commercial device to do that (and trigger external flash and shoot synchronised time-lapse).

He reads this forum and may even see this message.

CHDK used for a Bullet-time sequence
Welcome to mishra.tv productions

Re: DC Socket size on Canon Powershot models 1.1mm 1.3mm ??
« Reply #39 on: 26 / August / 2009, 05:58:53 »
The biggest problem so far was obtaining A450s and A460s. Took me 6 months to accumulate 50. Average price of 40-50 bucks each.

I hope to get this number to a 100 next year. I am shooting a feature film where this setup will be used.
CHDK used for a Bullet-time sequence
Welcome to mishra.tv productions

 

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