Although very uncharacteristic of me, I have already ordered the gear for the 3 units via the links in your blog post.
I have some solar chargers in a drawer, so may get that linked up pretty quickly. I also have some cheapo USB wifi repeaters that I've never put to use [similar to these, but cheaper https://www.fnac.com/mp40255673/Repeteur-Wifi-XIAOMI-Mi-WiFi-Repeater-2-...)
Some more about my use case.
In effect, I want to be able to "see around corners", our rural property is traversed by a public path, and locals (poachers, bikers, quads) and tourists have a tendency to go "off piste". I have already tested out the range of LoRa 433mhz enabled sensors that report back to the house when someone is approaching/leaving - but I still need some visuals to understand what is happening.
The ESP32 has Bluetooth, so, depending on proximity, that may be a way of turning the camera on, but I was instinctively thinking of adding a LoRa 433mhz board to act as an interrupt for the ESP32. I already have LoRa working with ESP32 on my home gateway.
As for your comments, I feel having to wait 10 minutes for a Wifi contact window to open is too long. I kinda meant sleep 55 seconds, listen 5 seconds - repeat, that could potentially extend battery life by 6 or 8. This would depend on the ESP32 being able to accept connect requests inside a 5 second window, as I said, I have never actually tried that before.