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?

Replies

- - - - ausdroid > iskess June 9, 2014 at 3:46am
        
        That would appear to be the case. You can do both on APM.
  - Rob Dunbar > Nejc May 1, 2014 at 7:01pm
    
    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.
    - Nejc > Rob Dunbar May 1, 2014 at 11:25pm
      
      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.
- Carl Schaefer > Marco Robustini March 16, 2014 at 11:47am
  
  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
  - Joey > Carl Schaefer March 17, 2014 at 9:28am
    
    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.
    
    Fritzing
    - Carl Schaefer > Joey March 17, 2014 at 12:29pm
      
      Great! Thanks guys for the help...
      
      Carl
  - Developer
    
    Marco Robustini > Carl Schaefer March 17, 2014 at 5:54am
    
    Some photos by Joey here...
Menno Hochstenbach February 22, 2014 at 6:09am

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

Thomas J Coyle III February 11, 2014 at 12:51pm

@Dave,

Try here: Virtual Pins

Regards,

TCIII ArduRover2 Developer
- RoboBill > Thomas J Coyle III March 5, 2014 at 7:39am
  
  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

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Using AUX pins as relays for CHDK

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