Hello, I'm an experienced programmer but new to CHDK.

I want to build a security monitoring solution for the end of a long driveway at the bottom of a hill, over 100m away.

I'm looking to purchase a new Canon camera (since I don't already own anything compatible with CHDK) to be remote controlled over USB from an old PC which is no longer in use, which will be running a modern Linux distribution to provide remote access.

The idea is the optical zoom on a Canon camera plus the megapixel resolution will be far greater than any normal security camera, and at a better price - in particular versus one which has wired networking or Wifi support built in.

I have been reviewing the forums and wiki and am a little confused as to how to determine which camera models support which features of CHDK (so far I assume all features are supported unless otherwise explicitly stated in the "Known Issues" section of the firmware page). Specifically, I want/need to be able to do the following:

1. Instruct camera to take a high-resolution photo with no flash at arbitrary intervals via USB connection.

2. Retrieve the photos from the camera over the USB connection.

3. Power camera via AC power (using an AC/DC converter)

4. In the event of a power failure ensure camera will be rebooted back into a mode which permits PC control.

5. Control optical zoom function (again in case of power loss should settings need to be manually reset).

It sounds like #1 should be no problem, and I've seen example scripts which perform #5. #3 I am assuming should not be a problem for any camera, though I will likely need to purchase a special AC/DC adapter.

I believe #4 is possible by configuring the SD card to be "bootable" but I've found conflicting reports regards actually getting the camera to automatically power back up. Ccan I just have the battery in place and when there's a power loss assume the battery will take over powering the camera? If so that would still mean periodically needing to remove the battery to recharge it manually. Some comments suggested using a zip-tie to force the power button to remain permanently depressed, in this thread: https://chdk.setepontos.com/d/2388

#2 Sounds like it could be fairly tricky. I've heard suggestions such as using CHDK to manually flicker an LED on and off, coupled with a separate optical sensor connected to the computer - in effect a binary protocol (morse code style) to transmit the images that way. Surely there is an easier method however?

Visiting my local electronics store, they have the following CHDK-supported models in stock (listed by increasing price)

IXUS 80 IS (8MP, 3x Optical Zoom)

A2000 (10MP, 6x Optical Zoom)

SX110IS (9MP, 10x Optical Zoom)

SX10IS (10MP, 20x Optical Zoom)

The SX110IS seems the best price/zoom ratio. The SX10IS costs twice as much as the IXUS 80IS. Unfortunately the A480, which costs half as much as the IXUS 80IS but has nearly identical stats, is completely unsupported.

Any advice regards what I am trying to do and/or specific camera recommendations or models worth further investigation would be most appreciated!

Cheers