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Multi-camera setup project.

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Offline waterwingz

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Re: Multi-camera setup project.
« Reply #160 on: 02 / September / 2014, 23:33:22 »
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Quote from: mphx on 02 / September / 2014, 14:47:40
Pfff it's gonna be messy to ground all these things...
You might think about using something like this :  http://www.ebay.com/itm/like/151098536728?lpid=82 but in the correct connector sizes for your hubs & fake batteries.



Insert one inline between each of your power supplies and hubs/fake batteries and use the extra plug to create a common ground buss with connectors like this :



Connect the ground side only between each power supply. Use normal wire on each tripod and heavy gauge between the tripod. 

I think this will not be too expensive,  will work well, looks tidy,  and is very portable.
« Last Edit: 02 / September / 2014, 23:35:36 by waterwingz »
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Ported :   A1200    SD940   G10    Powershot N    G16
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Offline mphx

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Re: Multi-camera setup project.
« Reply #161 on: 03 / September / 2014, 04:27:08 »
@waterwigz

let me see if i get it right... i get the first one and connect one side to the dummy battery and the one of the 2 other sides to the power cord of it.Second side that is left free , i end it with the second thing...
And then i connect with some kind of wire all the "second image" things through that green thing to create a common ground spot  or something?

If the above is correct it can be done for the dummies...i dont get it how can be done with hubs.

What was the other thing you said in earlier post?Connect the ground of one port of every hub all together?This will do partially the trick?
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Offline waterwingz

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Re: Multi-camera setup project.
« Reply #162 on: 03 / September / 2014, 08:36:15 »
Quote from: mphx on 03 / September / 2014, 04:27:08
let me see if i get it right... i get the first one and connect one side to the dummy battery and the one of the 2 other sides to the power cord of it. Second side that is left free , i end it with the second thing... And then i connect with some kind of wire all the "second image" things through that green thing to create a common ground spot  or something?
Correct.  You could also buy the appropriate male plugs & female jacks, suitable for mounting on a cable, and solder together to create your own adapter cables.

You are trying to make a short "patch" cable that does not interfer with normal operation but allows you access to the 0V conductor from the power supply.

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If the above is correct it can be done for the dummies...i dont get it how can be done with hubs.
The pictures you posted of your hubs show that is uses a "wall wart" style power supply that plugs into the hub to provide power.  See the center jack in this picture.

YOU ARE USING POWER FOR THE HUBS - RIGHT? 

You can connect the same style cable (perhaps with different sized plugs/jacks) between the power packs and the hub and then connect the other Y lead together and to the Y leads from the fake battery power supplies.

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What was the other thing you said in earlier post?Connect the ground of one port of every hub all together?This will do partially the trick?
I was just trying to suggest another method to get all the grounds connected.  The metal shield on the USB hubs or the 0V power pin on the USB jack might be all connected to the 0V line from the powerpacks.  You will need to check that with an ohm meter. If they are, then any method that connects them all together will help create a common ground point.

Edit : If I have a few minutes later today,  I'll try to create a wiring diagram that shows all of this.
« Last Edit: 03 / September / 2014, 08:59:16 by waterwingz »
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Offline mphx

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Re: Multi-camera setup project.
« Reply #163 on: 03 / September / 2014, 09:16:07 »
IMPORTANT UPDATE :)

Lets put your ideas on hold a bit waterwingz.

We took apart power cables from usb cables on every tripod.We didn't tied them up or anything..we just kept them far away apart.
Stability went high sky. 5 tripods connected for several minutes...without losing not a single one.Thats a first.
Usually we had random disconnects with only 2 tripods.
Probably there was too much interference from the power cords (don't forget that are chinese dummy battery kits) and some of them are making a high pitch noise....electricity must be doing party there...

More tests and will post results :)
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Offline waterwingz

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Re: Multi-camera setup project.
« Reply #164 on: 03 / September / 2014, 10:35:13 »
Quote from: mphx on 03 / September / 2014, 09:16:07
Lets put your ideas on hold a bit waterwingz.
Congratulations! You have just proven exactly what I was trying to tell you. 

Without proper grounding, every conductor in your wiring becomes an electrically floating antenna - transmitting and/or receiving noise at random.   With enough noise,  cameras will get confused and go offline.  In severe cases,  actual permanent electrical damage is possible.  And a really good source of noise is cheap switching mode power supplies.

One "solution" is to separate each cable as far away from all the other cables as possible, thereby lowering their ability to couple together and share noise.  You could also add shielding - with braided metal sleeves and or aluminium foil wraps.  At a minimum, run your USB cables away from the power cables to the fake batteries.

If you can get stability this way then that is great. But a better, more stable, and more reliable solution will still be to fix the grounding.

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Offline ahull

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Re: Multi-camera setup project.
« Reply #165 on: 03 / September / 2014, 10:51:09 »
Quote
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And a really good source of noise is cheap switching mode power supplies.
...

There is a reason why they are cheap... generally they have much poorer noise figures and worse regulation.

They are also inclined to have poor mains isolation too.

As I have suggested with other multi camera rigs, an ELCB or RCD mains breaker plug is a good idea. This should protect you from the rather nasty consequences if one of these cheap power supplies decides to pop and shunt mains voltage in to places it shouldn't go.

Having said all that, I have used quite a number of these cheap devices, and am still around to tell the tale. 
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Offline thepanoguy

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Re: Multi-camera setup project.
« Reply #166 on: 04 / September / 2014, 02:48:02 »
Power supplies are manufactured to ISO or EU Standards to protect people from mains voltage faults and potential electrocution. Switched mode power supplies are designed for specific specifications. Using certified ISO or EU Standards switched mode power supplies, outside their design specifications, can result in electrical hazards.

A successful earthing and electrical noise solution is the understanding of your local earthing system used by the mains supply authorities.

An RCD / ELCB will only protect from a active conductor (live or hot depending on your locality) to earth fault. An RCD / ELCB will not protect from an active to neutral fault. If the earth wiring and electrode is ineffective the earth path is potentially a neutral return conductor. Depending on the situation an RCD / ELCB may or may not trip or it can false trip intermittingly.

In my region (Perth, Western Australia) the supply authority distribute three phase and neutral 240 volts 50hz. RCD / ELCB’s protecting lighting circuits and power outlets are mandatory in residential premises. In the consumer switchboard, the neutrals are terminated into a neutral link and the earths into an earth link. The neutral and earth links are connected with an earth conductor which is run to the outside of the premises and connected to a earth electrode.

In essence, every premise is an earth electrode and when combined a massive earth conductor. The system works because my soil locality is fine sand with moisture.

Other regions use a dedicated earth conductor which is neutral earth bonded by the supply authority.

I have opened double insulated do not earth electronic equipment. In many cases the earth reference is derived from two metal oxide varistors connected in series across active and neutral. The centre tap is used as an electronics earth reference. The active side is connected to a fuse. In the event of a power surge the non-serviceable fuse blows rendering the equipment inoperable. 

In view that countries use different mains supply voltages and earthing systems, it may be helpful to all, if the moderators start a dedicated thread and members post and document their local mains distribution specifications and experiences. 
« Last Edit: 04 / September / 2014, 02:51:18 by thepanoguy »
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Offline novsela

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Re: Multi-camera setup project.
« Reply #167 on: 04 / September / 2014, 02:53:37 »
regarding the cables , please see how we done it
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Offline mphx

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Re: Multi-camera setup project.
« Reply #168 on: 04 / September / 2014, 03:21:29 »
@thepanosguy

In my region (Greece) , grounding is not something that is setup properly.My friend asked the electricity technician that he setup the electric stuff on the studio and he told him that even in more complex buildings , ground wire in the sockets is not even connected somewhere..just hanging in there...go figure...pathetic country with pathetic people when it comes to do a job right.

@novsela

i can't really tell much from the photo :)
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Offline andrew.stephens.754365

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Re: Multi-camera setup project.
« Reply #169 on: 04 / September / 2014, 05:08:50 »
Quote from: mphx on 04 / September / 2014, 03:21:29
...go figure...pathetic country with pathetic people when it comes to do a job right.

Don't be too hard on yourself - the British park F35's on golf-courses http://www.bbc.co.uk/news/world-europe-29056870 

Imagine what that must do to the grass :-)
« Last Edit: 04 / September / 2014, 05:20:12 by andrew.stephens.754365 »
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