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?

You are not right.

I think what you are referring to is the use of the new Canon DIGIC6 chip in some of the newer Canon high end models and the DIGIC4+ in some other models. The DIGIC4+ has been hacked in several camera models and there is at least one hack for a DIGIC6 based camera so far.

These changes have slowed things down but not stopped them. This is not the first time the CHDK developers have needed to overcome such obstacles. The entire camera operating system actually changed a few years ago for example (from VxWorks to DryOS).

Nothing is future proof. Canon could go out of business or stop making P&S cameras for example. Or Canon could make a simple firmware change and lock out CHDK forever. But they have not done so for over eight years now. And in the worst case scenerio, there are thousands of used and reconditioned cameras out there suitable for UAV work - a situation that is unlikely to change for a long time.

Replies

- - iskess > Hugues August 2, 2015 at 2:25am
    
    Is there a little residual voltage leaking from the signal pin when the Pixhawk relay is in the off state? It doesn't take much to trigger the transistor.
    - MR60
      
      Hugues > iskess August 2, 2015 at 3:35am
      
      I found the problem and will post shortly the correct circuit for the Sony A5000. Working now with Pixhawk!
      - Phil Horner > Hugues August 2, 2015 at 3:40am
        
        You guys are damned amazing.
    - MR60
      
      Hugues > iskess August 2, 2015 at 3:05am
      
      I tried to measure current flowing from the Pixhawk S pin to the base of the transistor (without resistor even) but my multimeter showed zero, even when trigger order is given from Pixhawk. It is like there is no current at all coming out of the S pin, which is not normal (or the casue is my multimeter is not able to measure small spikes of currents, which is probable).
      
      Any electronician in the room to tell us what is the simplest transistor design to switch a load to the ground ? Should not be complicated.
MR60

Hugues July 23, 2015 at 3:30pm

CHDK method does not seem future proof as of today's canon camera generation, if I understood well. This is because canon uses new chips inside their cameras that don't allow CHDK anymore. Am I right ?
- Walter Wing > Hugues July 23, 2015 at 3:55pm
  
  You are not right.
  
  I think what you are referring to is the use of the new Canon DIGIC6 chip in some of the newer Canon high end models and the DIGIC4+ in some other models. The DIGIC4+ has been hacked in several camera models and there is at least one hack for a DIGIC6 based camera so far.
  
  These changes have slowed things down but not stopped them. This is not the first time the CHDK developers have needed to overcome such obstacles. The entire camera operating system actually changed a few years ago for example (from VxWorks to DryOS).
  
  Nothing is future proof. Canon could go out of business or stop making P&S cameras for example. Or Canon could make a simple firmware change and lock out CHDK forever. But they have not done so for over eight years now. And in the worst case scenerio, there are thousands of used and reconditioned cameras out there suitable for UAV work - a situation that is unlikely to change for a long time.
  - Phil Horner > Walter Wing August 2, 2015 at 3:44am
    
    I don't know if Canon is aware how popular their cameras are due to CHDK, but I'm sure if they were they wouldn't be in a hurry to lock us out.
  - MR60
    
    Hugues > Walter Wing August 1, 2015 at 1:26am
    
    Yes that is what I was referring too. Thx for the info, this is good news CHDK found hacking ways through these new chipsets. Let's hope it continues like that.
  - Plinio Augusto > Walter Wing July 23, 2015 at 10:59pm
    
    Hello Walter,
    
    What do you think about AF lamp flashing at the time of the shooting? You have developed a script for that?I read some posts about it, it seems a good solution for the moment.
    
    Regards,
    
    Plínio Augusto
Developer

Craig Elder July 22, 2015 at 1:49pm

We have this Open Camera Control board http://planner.ardupilot.com/wiki/other-project-and-common-topics/c...

that listens to the MAVlink stream for camera control trigger messages and will send CHDK commands to a camera. It also writes a logfile to the SD card in the camera with Time,Lat, Long, Heading, Pitch, Roll, Altitude annotation information as each photo is taken. At the end of the flight the file can be read and used to populate the EXIF data for each photo.

The board has been finished for about 18 months but 3D Robotics decided to not produce it. It is open source hardware and software and we are looking for other companies to produce the board.

I have spoken with a few manufacturers but I would be interested to talk with more. Also is there enough interest in this group to purchase the board if it is manufactured ?

Thanks

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Using AUX pins as relays for CHDK

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