Arduino controling a DSLR shutter dangerous or not

Discussion in 'Embedded Systems and Microcontrollers' started by cvangordon, May 8, 2018.

  1. cvangordon

    Thread Starter Member

    Mar 28, 2016
    31
    1
    im working on a project that will use an Arduino uno to release the shutter on my pentax k50 DSLR. The simplest way of getting the shutter to fire with a signal from the Arduino came from this Youtube video:

    The method in the video im interested in starts at the 2:00min mark.
    Many people online have described making a shutter control this same way but with several saying that there needs to be an optocoupler used for safety.
    The way the shutter release works is by actually grounding the current on the tip of the jack rather than sending a pulse.

    With all that said is the method in the video likely safe even though it doesnt use an optocoupler? With voltages from the Arduino pin only being 5v and the voltage of the shutter release typically being around 3.3v is there any real danger of damaging circuits anyway?
     
  2. DNA Robotics

    Active Member

    Jun 13, 2014
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  3. Grum

    New Member

    Apr 30, 2018
    23
    0
    First of all, I'd be sure to find out exactly how YOUR camera can be remotely triggered - the demonstration in the video is a Canon, which I think is slightly different from my Nikon, and your Pentax may be different again - the lesson being "don't assume that they can all be triggered simply by a 'short' across two terminals". If the remote trigger functions are simply activated by shorting the tip to the sleeve, then I would certainly do that using some form of isolation between the battery and circuitry in the camera, and the power for your Arduino. An optoisolator is a simple option. I've used a similar concept using an Arduino to register a dropped item breaking an IR beam, and then triggering a flash to fire after a preset delay. The trigger action is sending a digital pin high briefly and then low again. The digital pin is connected through one side of an optoisolator to ground, and the other side of the optoisolator forms the 'switch' across the pins of the flash, that cause it to trigger. Although the optoisolator has an LED inside it acting as a load, I added a current limiting load resistor, just to make sure I didn't suck too much current through the pin - I think the documented max is 40mA per pin, with a suggested max of 20mA - I'd be looking for much less. I used a 470R in my circuit which held the current down to about 7-8mA, and that is applied only for a few milliseconds. In MY case, I am more concerned about protecting the Arduino from the huge amount of power that is discharged by the flash, rather than the other way around ;-)
     
  4. Sensacell

    Moderator

    Jun 19, 2012
    2,305
    736
    "Most" modern DSLR camera's can be triggered with a simple NPN transistor switch to ground.
    The chances of damaging the camera with this setup are remote, I would not bother with an isolator unless there is mains-powered gear connected.

    Find and measure the open circuit voltage on the SHUTTER input, (usually 3.3 V)

    You can measure the required current by triggering it with a 10 ohm resistor, measure the voltage drop on the resistor while it's triggered.
    Calculate the current from that- probably a few mA.
     
  5. be80be

    AAC Fanatic!

    Jul 5, 2008
    1,768
    347
    Any npn like a 2n2222 would work 1 k on the base and you be good.
     
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