Advice Wanted: Making a DIY AC/DC PSU for Pentax K-X DSLR.

Discussion in 'The Projects Forum' started by jaq1967, Feb 12, 2012.

  1. jaq1967

    Thread Starter New Member

    Feb 12, 2012
    3
    0
    Hi,

    I'm new here and need advice on a small project I am about to embark on.

    I have a Pentax K-X DSLR camera that is powered by 4 x AA battery cells. Pentax do make a mains adapter for this unit which is hard to get hold of and costs around £100.00. It looks simple enough and from what I have seen it has an output of 6.5V and 3A. Connectivity is via a twin dummy AA cell unti that plugs into where two of the AA cells would sit.

    I'm in the process of making the adapter unit using two AAA to AA converters and these are wired up with a CCTV tail that has a 2.1mm female power connector (pretty standard).

    What I am struggling with is finding a power supply that matches the one from Pentax. Could I get away with using a PSU with a different voltage and amperage?!? There are loads of 5V PSU out there with various Amps and was wondering what I could use safely without running the risk of blowing my camera up.

    I got my inspiration from a website (I can't understand what it says as it seem chinese to me!):

    http://www.welcome.zaq.jp/moonlight/k-m.html

    You may wonder why I want to do this? I do Astrophotography which requires long exposures and the outside temperature is generally low. I use rechargable battery's but once I start shooting I can't move anything. If the battery's die that is essentially it! A PSU unit would by pass this.

    Thanks in advance.

    Jaq
     
  2. Markd77

    Senior Member

    Sep 7, 2009
    2,803
    594
    As long as the current is 3A or over and the voltage is 5V - 6.5V you should be fine.
    I'm basing this on the pictures at the bottom which show it working at 5V.
    Get a good quality regulated supply and it's probably best to get a cheap multimeter and check that the voltage is actually right.
    Another option might be to get 4 rechargable D size cells. They can be found in high capacities if you look around a bit.
     
    jaq1967 likes this.
  3. jaq1967

    Thread Starter New Member

    Feb 12, 2012
    3
    0

    So would something like this be OK?

    http://cpc.farnell.com/ideal-power/5206-20s05-v-3a/psu-desktop-5v-4a-3-pin-iec/dp/PW01485

    or...

    http://forum.allaboutcircuits.com/newreply.php?do=newreply&p=455196

    or...

    http://cpc.farnell.com/powerpax/ptd-0540peu/ac-dc-power-supply-5v-4a-2-1mm/dp/PW02773


    I'm not to big on electricity but the Amp issue is less critical as long as equal to or greater than 3A?

    5V seems to be more common than 6V. I can't even find a 6.5V. 5V is OK then? (...it should be as I'm using 4 x AA rechargable Eneloop's at moment).

    Thanks for your advice.

    Jacques
     
  4. Markd77

    Senior Member

    Sep 7, 2009
    2,803
    594
    They both look good (the middle link doesn't work).
    The camera just takes as many amps as it needs, most of the time it will be far less than 3A. Having a supply capable of more than 3A won't make the camera draw more current.
    5V should work, it's mentioned a few times on that link and its around the same voltage as 4 well charged NiMH cells.
     
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  5. jaq1967

    Thread Starter New Member

    Feb 12, 2012
    3
    0

    Thanks for the advice. I was worried that it may be the issue with the amps that would kill the camera but clearly not - from what you say. Voltage seems to be the key and 5v should be OK. I got my hand on freebie from the CCTV dept., at my place of work. A regulated 5v 2.6amp DC (centre +ve). They said it may work and if anything if it didn't it won't kill the camera. I imagine maybe at that ampage the camera may just show the battery indicator on the DSLR as half charged rather than full.

    I'll see how it goes and will let you know.

    Thanks again.

    Jacques
     
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