Connect with us

powering 36 DSLR cameras from a single powersupply

Discussion in 'Power Electronics' started by Adrian S, Jan 4, 2019.

  1. Adrian S

    Adrian S

    7
    0
    Jan 4, 2019
    Hi there.

    I am a total novice when it comes to understanding power supplies and the like. Last year I built myself a multi-camera rig in order to produce realistic human 3D models for animation. I am looking this year to improve on my build. One such area for improvement would be its power supply. Currently each camera has a dummy battery connected to a mains transformer ( https://www.amazon.co.uk/PremiumDigital-Canon-Replacement-Power-Adapter/dp/B00841UIOU )... very messy cables and lots of multi plugs. I would like to remove all the individual power supplies and replace them with a single transformer or even a couple to service all the cameras. At the moment the rig uses 18 canon eos 400d cameras but I plan to double this number so wish to accommodate scalability. Any formulas on how to calculate what I would need a transformer to deliver or any help/guidance would be much appreciated (I do dislike having to cable tie transformers together to try to make them tidy)
     
  2. BobK

    BobK

    7,645
    1,663
    Jan 5, 2010
    Easy. Multiply what one camera needs by 36. The current that is, the voltage stays the same.

    Bob
     
  3. Adrian S

    Adrian S

    7
    0
    Jan 4, 2019
    Thankyou Bob that does make it sound easy :) So.... how would i work out what each camera needs..... the only figures I can see are DC 8.1v on camera body, 7.4v 720mah on batteries and output 7.4v 2A on the power adapters. Is there a way I can test the current draw of the camera or should i use the batteries 720mAh (7.4v 26A) or the power supplies 2A (7.4v 72A) as a guideline ?
     
  4. BobK

    BobK

    7,645
    1,663
    Jan 5, 2010
    Do you have a multimeter?

    It does not use 2A or the battery would last about 20 minutes at most.

    Bob
     
  5. Adrian S

    Adrian S

    7
    0
    Jan 4, 2019
    Yes I do have a multi meter (only used it to check for continuity). but have literally just finished watching a vid on testing current.. something for me to do over the weekend. Thankyou for your help , I am definitely moving in the right direction now. The only thing that Is confusing me now is the voltage side of things.. I can find lots of 12v supplies that offer varying amounts of wattage. For example I already use one of these https://www.wholesaleledlights.co.uk/led-strip-lights/led-power-supplies/150w-led-driver.html to power 7m of led strip lights.. are these the types of units I should be considering https://www.tme.eu/gb/details/hrp-300-7.5/built-in-power-supplies/mean-well/ (once i've worked out the draw).
     
  6. BobK

    BobK

    7,645
    1,663
    Jan 5, 2010
    Measuring the current might be tricky. The camera likely draws a burst of current when you take a shot. If all 36 are triggered at the same time, you have to allow for that max current. You might not be able to read it with the multimeter. A storage scope would be better, but I doubt you have one of those.

    Bob
     
  7. Adrian S

    Adrian S

    7
    0
    Jan 4, 2019
    you're absolutely right.. I don't have a storage scope.
     
  8. Alexey-Budka

    Alexey-Budka

    1
    0
    Mar 18, 2019
    We were dealing with a similar issue. Our project also involved finding a better way of powering our 12 cameras array ('bullet time' booth) for upcoming events. The task was also to replace the pile of spaghetti cables with something reliable and simpler, that will not take too much space in the array. Cable management was also important as the set up had to be quick and this was the biggest time suck.

    We looked into building our own (ultimate) power supply that would accommodate all of the cameras, but realized that it would require more time than anticipated as the reliability was a concern, so we just gave up. Then we found esper powerbox https://www.esperhq.com/product/multi-camera-power-supply-powerbox/ supplys power to 6 cameras per box from a single wall outlet. It works with cameras that operate from 7.4v (I think up to 9v) by connecting them to the box via dc couplers. It is also great for troubleshooting.

    Alexey
     
  9. Adrian S

    Adrian S

    7
    0
    Jan 4, 2019
    wow £400 for 1 box. That's a lot. In the end after testing the amount of power required for each camera I have gone with a
    meanwell RSP-320-7.5 300W 7.5V 40A https://www.powersuppliesonline.co.uk/rsp-320-7-5-300w-7-5-40a-enclosed-power-supply.html which is doing the job admirably, it doesn't look so pretty I must admit, but I am considering buying a 3D printer to make my own electronics enclosures.
     
  10. dave9

    dave9

    819
    193
    Mar 5, 2017
    ^ Putting that in an enclosure will tend to cause it to recirculate the heated exhaust air, so it runs hotter and then should be derated for lower max output, unless your enclosure has a fan added too and/or is partitioned to isolate intake from exhaust. Your PSU is roughly the ideal voltage at 7.5V, to run a 12VDC, brushless ~ 1200RPM fan nearly inaudibly, just about any 12V fan will run (at lower than the ~1200RPM spec) at 7.5V.


    You might be as well off just painting it if you want color and putting a cap on the end where the wire terminals are exposed, and if anyone else has access to it, a Warning High Voltage label on the cap, and/or securely screwed down if warranted.
     
    Last edited: Mar 18, 2019
  11. Adrian S

    Adrian S

    7
    0
    Jan 4, 2019
    Good plan....A lick of paint sounds the cheapest option and a cover for the terminals... 3D printers is a future project.
     
  12. Bluejets

    Bluejets

    3,541
    718
    Oct 5, 2014
    Be aware that running "miles" of low voltage cabling will create the need to calculate any voltage drop and adjust cable size accordingly.
    Which at 12v can be substantial at times.
    It can be minimised by connecting the low voltage supply lines in a star configuration.
    Didn't see any current requirements so cannot comment on just how much effect.
     
  13. Adrian S

    Adrian S

    7
    0
    Jan 4, 2019
    Well...... each camera draws no more than 1amp and I will have a maximum of 5 cameras on each stem (point of a star). Each of the 6 stems has embedded in it approx 1.5m of 18 awg wire with 5 sockets spliced into it at approx every 12cm (in parallel). Between these sockets and the cameras will be an inline 3 amp fuse to a dc coupler. Each stem will then go directly back to the power supply with an inline 10 amp fuse. At the moment, on testing, each socket provides 7.5v (the supply is adjustable a good 3+v either way). I plan to start connecting up cameras 1 at a time whilst checking voltage and current draw with each camera added, just waiting for 6 couplers for the 600D's to arrive from china.
     
  14. FuZZ1L0G1C

    FuZZ1L0G1C

    367
    115
    Mar 25, 2014
    As for measuring the (idle) load of a DSLR, I came up with this idea to test my camera (a Pentax K2000 SR) load:
    (Presuming your 400d's also use AA cells).
    Cut a piece of paper or thin card / plastic to the size diameter of one cell - cell 'bridgepiece' which should be on lid.
    Cut 2 lengths of thin, insulated hookup wire, strip ends and bend bare ends into 'sheperd's crook' shape.
    Carefully glue these on each end of the 'insulator strip', without contaminating outer 'contact' side of bare wire.
    Wire connections must align with the (+) and (-) terminals of their cells.
    Ensure wires are not shorted.
    Lift battery-housing cover, place your series power-splitter device centrally on top of both cells, feed the pair of wires (if possible) via a gap such as the hinge area..
    Mark the polarity with red marking pen.
    Or, you may have to score either lid or body a bit to make it fit.
    I found that my batt cover wouldn't click all the way closed, but got it to slide home enough to connect all cells correctly.
    Then temporarily bound it with a large elastic rubber band around body.
    Now you can hook up a meter, digiscope, etc to measure the current (series, so doesn't matter where in the 'loop' you place the insulated splitter / ammeter.
    But, as @BobK sez at #6, there will likely be a spike or peak "burst" when flash / mirror solenoid / processor circuits are fired.
    A DMM with "peak hold" function could maybe store this value.
     
  15. dave9

    dave9

    819
    193
    Mar 5, 2017
    ^ To measure battery drain of various devices I made a (similar?) thing, I used copper clad fiberglass board so thin that the surplus place I bought it from called it "scissor cut", and indeed the giant Wiss scissors I have can cut it.

    I soldered wires onto both sides of a long thin strip of it, sanded and polished the cut edges so it would slip between a battery and the device contacts easily, then onto the wires I soldered on sockets/barrels/whatever-they're-called, with the right diameter to accept multimeter probes.

    ... or I could have misunderstood what you meant! My attention span these days seems to be about 20 seconds long and that's my own fault.
     
    FuZZ1L0G1C likes this.
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-