Using AUX pins as relays for CHDK

I'm confused and a bit frustrated, would appreciate any help as I'm not sure how to proceed.

Setup: I have a pixhawk autopilot running Arduplane 2.77, using Mission Planner 1.2.95

I've been following this guide to get my CHDK enabled camera working with my pixhawk. I'm interested in getting the camera triggering based on distance traveled.

Obviously the guide was written with APM in mind, so it needs to be adapted a bit for pixhawk; specifically the setting for RELAY_PIN. I've kept the rest of the settings the same as in the tutorial.

Pixhawk has 6 AUX ports according to the quick start guide, I am assuming that the numbers above the pins correspond to the AUX port numbering. When you mouse over the RELAY_PIN parameter, it says that pin 54 corresponds to Pixhawk FMU AUX1.

Tried setting RELAY_PIN to 54, no joy. Did a bit more looking, discovered in the release notes for 2.77: 

"Improved relay code
The relay and servo set code has had a major overhaul, with up to 4 relays now supported for MAVLink control and much better support for the DO_SET_SERVO, DO_SET_RELAY, DO_REPEAT_SERVO and DO_REPEAT_RELAY MAVLink commands. Along with these changes is a new parameter BRD_PWM_COUNT which allows you to specify how many auxillary PWM outputs to enable, with the remaining outputs being available as digital relays. This allows you to re-assign some of the aux servo outputs on Pixhawk for use as relays, by setting the RELAY_PIN, RELAY_PIN2, RELAY_PIN3 and RELAY_PIN4 parameters. The pin numbers for these pins start at 50 for the first aux servo pin, and go to 55 on Pixhawk."

Additionally,I found this github issue about this same problem that states that the Pixhawk can't trigger CHDK because its relay pins operate at 3.3V instead of 5V.

So i suppose my specific questions are:

1) Is AUX1 pin 50 or 54?

2) Can anyone confirm that the relays, when working properly, won't be able to trigger CHDK?

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Replies

            • That would appear to be the case. You can do both on APM. 

      • Nejc,

        Which firmware are you running on Pixhawk? Camera  trigger works on Arducopter 3.1.3 but not on Arduplane 2.78b or 3.01.

        • Rob,

          I am running Arducopter 3.1.3. I just got it working, but with using relay for CAM TRIGG TYPE, and connected to AUX 5.

          I am still wondering why isn't working right with servo Trigg type.
    • Hi Marco,

      Could you help me out and post a picture of your assembled device. I'd really like to build this so I can get the 5v necessary to trigger my CHDK script off the pixhawk but I have nil experience reading electronic schematics and how they translate into the actual assembled piece. I can solder (and occasionally burn my fingers) so any help on a picture and details for this noob would be appreciated.

      Thanks,

      Carl

      • Here's a breadboard diagram made with fritzing. I substituted 2N3904 and 2N3906 in place of the BC547 and BC557 since they're easier to find in the US. Hopefully this helps.

        3702643149?profile=original

        Fritzing
        • Great! Thanks guys for the help...

          Carl

      • Developer

        Some photos by Joey here...

  • Hi Dave, you say you're using Ardupilot code on your pixhawk. Do you know how to edit this code (Arduplane 2.77) and build and upload it to pixhawk?

    Thanks, Menno

  • Admin

    @Dave,

    Try here: Virtual Pins

    Regards,

    TCIII ArduRover2 Developer

    • Thomas

      I have two Dimension Engineering "Doubleswitch" relays on my rover. I need to turn these relays on or off at various waypoints during the rovers mission.

      I am assuming

      1) Set up two auxiary pins as PWM

      2) Plug the relays into these two "ports"

      3) Add some commands on the mission controller to turn on or off these relays.

      This is where I get stuck. I cannot find a tutorial as to how to set up these commands.

      Can you point me to the right tutorial

      Thanks

      Bill

This reply was deleted.

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