Hello camera trappers,

I am building a custom DSLR camera trap consisting of old Canon EOS 40D, wide angle lens, ATtiny microcontroller, PIR motion sensor and LDR to detect day/night.
For now, I am only interested in daylight operation, but in the future, I would also like to try night photos with flash, so I am seeking for suitable flash.

I did a little research and I found out that Nikon SB-28 is a great choice due to its excellent stand by power managment. But obviously there is a compatibility problem with Canon, I would need a custom cable (or wireless trigger) to implement wake-up function with half press of a shutter.

What is other option compatible with Canon? I found very little regarding canon stand by power managment, so I assume it just switches off the power to capacitor and recharges it only on wake (which takes few seconds). On the other hand, some newer Canon speedlites have ability to turn off power-saving mode, which will drain the batteries in a few days. Is there some Canon (or 3rd party flash for Canon) flash with similar power managment as Nikon Sb-28 has, so it can stay in ready-to-shoot mode for many days/weeks? Thank you!