Testing Camera via CHDK

I am completely new to Pixhawk and I am trying to get the CHDK cable to force my Canon S110 to take a picture manually from my tx. I have the Pixhawk out of the equation.

I have a camera with the CHDK firmware and script loaded and activated. The camera is set for remote activation. I have a cable for my Mobius that converts the USB to a three pin servo connector. Is cable sufficient to tell the camera to take a picture? In my simple test, I have my rc receiver direct connected to that CHDK camera and the receiver is powered by a 5v battery.

I am reading from different sites how some cables have relays in them. Is that a requirement? When is the relay needed? If my existing cable will work, is there a mapping of wires on the USB plug to the servo plug that I should verify? At the moment, the camera does not even acknowledge any input from the USB side. I figure either I have the wrong pin mapping on my cable or I need a special relay to convert the pulse width to something the camera understands.

If a relay is needed, does the AUX5 have the relay that I need? If so, how can I manually actuate it?

Thank you for your time


I did get the camera to snap with another cable that I took apart. The one I was testing with had the red wire disconnected and insulated in the plug.

What I have learned so far. Canon S110 camera just needs a 5v connection on the red and black wires of the USB cable. That translates to the left and right most pin in the plug. When the 5v is cycled, a picture is taken.

So for simple picture taking, I need a relay. Question is, does Pixhawk have the relay built into aux5? If so, then across which pins?

About CHDK. It seems you only need CHDK in the following situation:

  1. If you have no connectivity between the camera and your Rx or FC. Then you can use the intervelometer program to take a picture every X seconds. Not good for mapping but ok for the hobbiest.
  2. you want to have more control over your camera than just taking a picture. For instance, changing camera mode, zooming, etc. Then I think you need that Gentwire too as the pulses of the radio need to be converted to what the camera can understand.

I suspect that if you just need simple shutter snapping, either via manual rc channel or pixhawk, then no chdk is needed. Just a relay of some sort. Is this correct?

Late reply. Sorry.

If you want to take a picture with any Canon PowerShot camera by connecting to the USB connector then you need CHDK loaded and running. I wrote the CHDK code that makes this work so feel free to post questions.