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trigger a camera shorting 2 wires via pixhawk

Posted by andresiko on May 21, 2017 at 4:35pm

Hello all,

I want to trigger my camera shorting 2 wires (soldered to the shutter button of a nex7), and I'm quite lost. Any advice? do I need any extra device or can i just plug it to a pixhawk output port? How to connect?

The camera trigger is 3.1V, and shots a photo everytime is shorted to the ground cable.

Thank you in advance

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Replies

  • andresiko June 21, 2017 at 9:45am


    Summonforgottenthread

    Hello again!

    the postman gave me this "notsolittlething" few days ago3702382898?profile=originalAnd, despite my system is already working with no issues until now, I was wondering how to configure this "external relay" thing. Any advice about how to plug and configure in Mission planner?

    AND, at this moment I am wondering how to configure the preccision timestam thingy using the hot shoe of the camera, already soldered the wires in the camera, and its basically the opposite working way, now is the camera the one acting as a relay (shorts 2 connectors when taking a photo) and not sure about how to connect tshis relay to the pixhawk in order to record the cam message in the logs... Any advice will be more than welcome!


    iSkyMaster said:

    I have never personally used the relay pins on Pixhawk but this is what I have found. Read this article LINK


    It explains how to do it. Just make sure your camera ground is connected to Pixhawk ground as well.


    Please note Pixhawk will output 3.3V so if you camera can not handle additional .2 volts than;


    You can try an external 3V relay from Amazon $2.99 each LINK

    Also check this link GitHub


    Let us know if any of the above worked.

  • andresiko May 25, 2017 at 12:46am

    Thanks for the link John, But already solved the situation with cheap garbage that I had lying around...
    John Stuart said:

    Have you checked this guy's products out? He has two that are soldered to the shutter button, one with focus and shutter, the other with just shutter. Also an IR option but that has too much latency I guess:

    http://www.rc-flysoft.com/pages/switchidx_e.htm

  • John Stuart May 24, 2017 at 9:00am

    Have you checked this guy's products out? He has two that are soldered to the shutter button, one with focus and shutter, the other with just shutter. Also an IR option but that has too much latency I guess:

    http://www.rc-flysoft.com/pages/switchidx_e.htm

    http://www.rc-flysoft.com/pages/switchidx_e.htm
  • andresiko May 23, 2017 at 5:45am

    The problem of that switch is that it has no mechanical relay, and when it "switchs off" it still remains open to minimal current, and then the signal of the camera still flows. I know that my English skills suck, but I'm doing my best xD.

    BTW, today made 2 flights, 692 photos in total, no trigger miss, everything perfect! will see for how long the 3V relay can handle 5V! xDDD


    Asim said:

    I just looked at the spec of the switch you are using. I don't think you even need an external relay, that switch has a mechanical relay because its designed to control power. Do the following test.

    1. Check the connectivity between the two red wires on the JST connectors when the switch is off. It should show no flow of voltage on your meter. (Set meter for connectivity testing not voltage testing)

    2. Now turn the switch on and the meter should show a connectivity.

    You connect your camera shutter wires to two red wires. Black are grounds, just ignore them. Give it a shot.

    Make sure in Mission Planner you set the ON duration how long you want the switch to stay on.

  • MR60
    Hugues May 22, 2017 at 11:37pm

    Yes. The point is to act as a switch where the Signal In is connected to one of the Signal Out. If the current flow is not sufficient to drive the camera (in my case with a Sony NEX5 it is not an issue but it depends of course on the camera), this can drive a regular relay powered with higher current capacity.
     
    Asim said:

    Hugues,

    That looks like a video signal switcher using active components. Not a an on/off relay switch. He needs a contact on off switch. There is no spec sheet so I am just guessing it allows you switch between Video TX outputs as shown int he diagram below.

    3702376574?profile=original



    Hugues said:

    Yes you need an extra device called an electronic switch that can be controlled by a PWM signal (like a video switcher for example).

    So the video switcher has one control input, plugged to Pixhawk on one of the AUX port (three wires are used). When Pixhawk will trigger the PWM trigger pulse on that AUX port, it will bring the signal PIN to a predefined PWM value during a certain duration (configured in the parameters of Ardupilot, via mission planner for ex)

    The electronic switch will then connect (short) you two camera wires that are plugged on the other side of this switch.

    I personally use this one to do the job, although you could use any other PWM controlled switch :

    https://www.banggood.com/fr/FPV-Camera-3-Channel-3-Way-Video-Switch...

  • andresiko May 22, 2017 at 2:26pm

    Solved*******

    kinda temporary solution; using the electronic switch that i had hanging around, hacking it a little (I soldered the "line in" to the "aux" in order to have an 5V output when switching on via RC), and powering the relay with those 5V (yeah, this is the bad thing, the relay it's only for 3V!) I can trigger the relay via RC switch, and it triggers the camera.

    IMG_20170522_230537.jpg

    IMG_20170522_230340.jpg

  • andresiko May 22, 2017 at 11:25am

    @Asim

    My pixhawk is already connected to servos and BEC, (its on a plane with many flights) servos are only connected to the "main out" not to the "AUX out", but I also tried with 1 servo connected to "aux out" (in order to create a "load") and I did measure 3.3V without the relay connected, but when I connect the relay it goes down to 0.5V (as you predicted, relay coil will not work directly connected to pin 5).

    The enclosed circuit diagram is really far away from my capabilities.

    I assume that I am not following your guidelines correctly, little bit of lack of electronic knowledge as well as a little bit lost in translation...

    At this moment I am waiting for the item from your link (shown as already shipped), but still wanting to play with the relay that I bought this morning (still don't understand why does not work!)

    I have the "coil" directly connected to the pin54 and to the ground, Pixhawk powered via power port, servo main out powered with the Motor ESC/BEC and connected to the laptop via USB. I have not tried the scheme shown in your post, but if you think I can reach results today trying new things will be happy to play with it again

    @Hugues I have tried also with an electronic switch, but looks like it's not appropriate for this task, it kind of maintains the switch closed to small amounts of current (like the needed for the camera triggering short circuit)

    @Asim "Fiesta" from Hemingway will open your eyes about one of the best cities of Spain and one of the best parties of the World!

  • MR60
    Hugues May 22, 2017 at 10:31am

    Yes you need an extra device called an electronic switch that can be controlled by a PWM signal (like a video switcher for example).

    So the video switcher has one control input, plugged to Pixhawk on one of the AUX port (three wires are used). When Pixhawk will trigger the PWM trigger pulse on that AUX port, it will bring the signal PIN to a predefined PWM value during a certain duration (configured in the parameters of Ardupilot, via mission planner for ex)

    The electronic switch will then connect (short) you two camera wires that are plugged on the other side of this switch.

    I personally use this one to do the job, although you could use any other PWM controlled switch :

    https://www.banggood.com/fr/FPV-Camera-3-Channel-3-Way-Video-Switch...

  • andresiko May 22, 2017 at 8:36am

    found it, my fault, as expected!

    the Voltage went only to 0.5 because the relay was connected, and did not receive enough intensity to activate =/.

    Proper relay shipped, will report back as soon as it arrives.

    Thank you from a city much better than Marbella!

    30.22.7.003.0010 - Finder - Sub-Min.DIL - Relay - DPDT - 2A - 3V - DC - coil - AgNi+gold - plated -…
    30.22.7.003.0010 – Finder – Sub-Min.DIL – Relay – DPDT – 2A – 3V – DC – coil – AgNi gold – plated – contact – wash – tight – 200mW
  • andresiko May 22, 2017 at 8:02am

    I may have not explained myself, or I'm not understanding your point. When not triggering photos there is 0.0V between "-" and "signal". When triggering the photo (set to 2.5s duration) this voltage goes up to 0.5 for those 2.5s.

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