I am having trouble connecting the 555 trigger to the A495 camera because the A495's trigger is on a very tiny plastic ribbon, and where it plugs in the leads are miniscule. So I don't think it'll be reasonable for people to open their cameras and attach there.
Instead, I'm exploring how I could connect the 555 timer to the two cameras via the USB port. This will require the CHDK but since they're all the same model, we can have a hard link to the correct firmware to put on your SD card, and a video on how to put your camera in CHDK mode. Now I'm sourcing cheap mini-USB cables and going to test it out.
- http://chdk.wikia.com/wiki/A495 (has beta firmware)
- Overview on USB triggering with CHDK: http://chdk.wikia.com/wiki/USB_Remote_Cable
- Instructable showing it with pictures: http://www.instructables.com/id/Remote-for-Canon-Compact-Cameras/
- Brooxes.com has some very sophisticated solutions for this problem, good to take a look at, as they've all surely been tested a lot: http://brooxes.com/newsite/BBKK/BBKK-PARTS.html
Totally open to suggestions, just trying to work around an unexpected issue with the trigger not being easy to solder onto.