I happen to have two Canon A540s that I've modified by hooking a wire up to the 2xAA battery input to provide power from a pc power supply.
The kit had an AC plug for the overhead light, so I decided to "do as they do in Rome" and use the bulky pc power supply to power both cameras, as well as trigger them:
I had two unknowns:
(1) Will 3.3V trigger both cameras?
(2) How can I run all of that wire without it getting tangled/in the way?
(1) Was easy to test, applying the same 3.3v that powers both cameras to the USB ports successfully triggers them, I used an easy-to-press power button from an old computer:
(2) Required some engineering, I used the pivot point of the handle to erect a small structure that would guide the wires:
I also have some pics of the prototypes, and the artwork for a laser cutter or similar cnc machine:
- The first version I built. Requries epoxy to hold it to the hex head.
- My current version. It uses a set-screw to hold the structure to the hex head.
