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

- iskess > Craig Elder July 23, 2015 at 11:36am
  
  Fantastic! Will it work with a Sony NEX or a5100?
  - Developer
    
    Craig Elder > iskess July 24, 2015 at 5:51pm
    
    The board is designed to communicate to a Sony Lan-c protocol enabled camera. I don't know if either of those camera support Lan-c
  - Za Pf > iskess July 23, 2015 at 2:49pm
    
    With the appropriate cable, yes. the a5100 uses a different pin for activating the shutter. you can find a cable on ebay and modify it, that is what I was planning. chdk / canon cameras just need the 5v and ground lines on any standard mini / micro usb cable
    - iskess > Za Pf July 23, 2015 at 4:29pm
      
      I'm sorry about my poorly worded question, I know about the multiport plug requirement for the Sony cameras, that's what I'm using. I was wondering if the Open CCB could control other functions on the Sony, namely focal length. Imagine if focal length could be controlled automatically by the Pixhawk to adjust in relation to the terrain data. We could fly level flight lines and maintain a constant GSD (within the constraints of sidelap and overlap)
      
      Other than gaining more camera control, what advantage does the Open CCB have? Is it simply that I can find the log files on the camera's card rather than the Pixhawk's.
- T3
  
  Thorsten > Craig Elder July 22, 2015 at 11:22pm
  
  Hi Craig,
  
  thanks for sharing! I came across it some time ago and was wondering why it hasn't been mentioned earlier - but maybe I just missed it :-) I am sure it has great potential. The only thing which makes it less attractive for mapping is the weight. It is the board, the cables (USB Type A) materials to mount it, ... Hence, for long endurance mapping missions smaller devices based on Marco's and Reuben's circuits have an advantage. Based on Za Pf's PCB you can make a device of about 2g incl. cables (see below). But for sure it is missing all the flexibility of the OpenCCB.
  
  So Kickstarter or Indiegogo is a good idea I guess.
  
  Cheers,
  
  Thorsten
- Plinio Augusto > Craig Elder July 22, 2015 at 9:10pm
  
  Thanks for sharing your response. Perhaps the solution is in Kickstarter or Indiegogo.I would be happy to buy your board. I'm sure many people are in need of this board.I think most people have not understood the importance of making georeferenced images with precision timing.
Reuben July 3, 2015 at 10:57pm

Hi Guys

Has anyone have any trouble getting a APM2.5 to run a relay on A09 .?.its supposed to have 5v logic but refuses to operate a 3v relay with a coil load of only 16ma ? when i operate the trigger from MP I only get 2.5v on A09 pin.

Regards Reuben
Za Pf June 30, 2015 at 10:46am

I'd like to be able to provide the cables required for sony cameras (a5100 / a6000 etc) as well. I'm going to start wading through this thread again, but does anyone know the particular pinout needed for that? I was under the impression the sony plug is just a micro usb with a different pin connected for the remote trigger. I guess I could manually strip this for use: http://www.ebay.com/itm/231256005313?ssPageName=STRK:MEWNX:IT&_...

I'm guessing its the ID pin (used normally for otg cables and such) or am I mistaken and its completely proprietary?
Za Pf June 30, 2015 at 10:34am

I made a version of reuben's circuit and put it on oshpark. my breadboarded version worked, still need to test this one. Very cheap if you want to build it yourself however.

https://oshpark.com/profiles/Zapf

OSH Park ~ Profile for Zapf
- T3
  
  Thorsten > Za Pf June 30, 2015 at 11:45am
  
  Hi Za Pf,
  
  thanks a lot for sharing! I have only tried Marco's circuit so far (see page 6) and it works great. But your design is easier to handle. I'll try it for sure and I hope they'll place it in the wiki!
  
  Cheers,
  
  Thorsten

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Using AUX pins as relays for CHDK

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