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Changing AC plug to battery operated

Discussion in 'Power Electronics' started by Victoria Nowrangilall, Mar 31, 2018.

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  1. Victoria Nowrangilall

    Victoria Nowrangilall

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    0
    Mar 31, 2018
    Hi,
    I hope this is the right forum to post this in - I have a small (disassembled) security camera that needs wall power to operate. My team and I want to use this tiny camera to put in our high-powered rocket to video our rocket's flight. To do this, I need to get the camera to run on batteries. Would this be possible, and if so, what measurements would I have to take to get an equivalent battery?

    Also, here are some specs printed on the plug:
    INPUT: AC 110-240V
    50-60Hz/01A
    OUTPUT: DC 5V +/- 0.5V 1000mA +/- 50mA

    And I attached a picture of the entire assembly.

    Thank you in advance!
     

    Attached Files:

  2. KJ6EAD

    KJ6EAD

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    Aug 13, 2011
    You probably can power the camera with a small battery pack. Measure the voltage where the red and black wires from the power supply board enter the camera board. Expect 5V with the red wire being positive but since I can't assume there are no other conversion or regulation components on the power supply board, it may be less.

    How do you intend to capture the video signal?
     
  3. Bluejets

    Bluejets

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    1,081
    Oct 5, 2014
    In case you are unaware, there are inexpensive miniature camera/transmitter units as used in FPV on quads etc. that may be suitable.
     
    hevans1944 likes this.
  4. WHONOES

    WHONOES

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    May 20, 2017
    Yes there are. But they have a limited range if you want to transmit directly to a ground base.
     
  5. Bluejets

    Bluejets

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    Oct 5, 2014
    How far would you like to go?
    Have seen at least one that works well at 2klm plus.

    Now the video is about range testing the actual controller transmitter BUT the camera transmitter operates at the same range.

     
  6. KJ6EAD

    KJ6EAD

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    Aug 13, 2011
    There's been no indication from the OP that they intend to transmit to ground. It serves little or no purpose to do so.
     
  7. Hopup

    Hopup

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    Jul 5, 2015
    I'm pretty sure camera in your picture will give you bad quality. You might want to use something better quality for this purpose. Small FPV cameras are usually good for bright environments what you will face by using it on the rocket.

    If you want to record video, there are cheap and very small DVR recorders available.
     
  8. BobK

    BobK

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    Jan 5, 2010
    You could use a small "power bank" used for charging cell phones. If they are too big, you could make one with a smaller battery, but that is more complicated.

    Power Bank

    Bob
     
  9. dave9

    dave9

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    Mar 5, 2017
    A rocket flight is generally short and light weight can be paramount.

    Sever the 5V positive supply to the camera and put it in series with a multimeter to measure current consumption. This will tell you the minimum Li-Ion battery size you need, capable of that current. Finding the tiny battery packs' current ratings is the more difficult part, or determine the max weight it can be an see if a battery of that weight will work, or else the project is a non-starter.

    The second issue is minimum voltage. If you're lucky the camera can operate down to the minimum safe discharge voltage of a Li-Ion cell, then you just need a cutoff circuit in series to protect the cell. Either using a variable voltage lab power supply, or getting creative with silicon and schottky diodes in series, you can lower the input voltage to the camera to see how low the voltage can go and based on this, determine if one Li-Ion cell is sufficient or whether you need two in series then a buck circuit to arrive closer to 5V.

    After you've determined the minimum battery size that will supply enough current, then there is the required runtime. The rocket will probably reach apogee within a few seconds but if you want to record it parachuting down too, a minute of runtime would be a better goal.
     
  10. Victoria Nowrangilall

    Victoria Nowrangilall

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    0
    Mar 31, 2018
    I was thinking to disconnect the transformer and connect the camera directly to a battery pack (as you suggested) after making proper measurements. The underside of the PCB that has the camera attached has an SD card slot to which the video saves to, so we won't be seeing it in real time.
     
  11. Victoria Nowrangilall

    Victoria Nowrangilall

    3
    0
    Mar 31, 2018
    The quality isn't too bad actually! I've tested it with the wall plug and looked at the video from the SD card, and it seems to be okay. The problem is that we are very short on time and have a bunch of other things to prepare and test as well...
     
  12. Bluejets

    Bluejets

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    1,081
    Oct 5, 2014
    To be fair, there is nothing to indicate the Op did not want to transmit to ground.
     
  13. KJ6EAD

    KJ6EAD

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    159
    Aug 13, 2011
    No; didn't rule out a potato battery either. I make some reasonable assumptions to limit scope. ;)
     
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