I look for a software (over gnu/linux) for digital trigger especially for canon SX510HS or physical circuit to control the camera to distance
Not sure if your camera is supported, but there is Entangle: https://entangle-photo.org/
gphoto2 --capture-image
*** Error ***
Sorry, your camera does not support generic capture
ERROR: Could not capture image.
ERROR: Could not capture.
*** Error (-6: «Unsupported operation») ***
I did not find any in PIXLS.US - Software
I search this. But no if it is very safe
Since it has wifi, there is likely an iOS/Android app to control it from your smartphone.
If I can do this, sure from gnu/linux also.
I install the CHDK but todavia can not capture of remote way. Or I do not find it still. I can is to use DNG, and has a lot of but options.
With the CHDK can use USB like remote control plugging and unplugging the camera
They would have to put CHDK in the list of software http://www.mighty-hoernsche.de/
I love these. A real Droste. The Panasonic android apk. Using wireless remote connection. Taking a photograph of itself.