Cameras could be built using a single board computer (like the Raspberry Pi Zero, but there are better and cheaper options) plus a USB camera module, and the ne

Cameras could be built using a single board computer (like the Raspberry Pi Zero, but there are better and cheaper options) plus a USB camera module, and the necessary firmware that could well be just a simple script invoking ffmpeg or similar streaming software; all Open Source. For example: https://www.friendlyelec.com/index.php?route=product/product&path=69&product_id=244 https://www.friendlyelec.com/index.php?route=product/product... https://www.friendlyelec.com/index.php?route=product/product&path=78&product_id=245 https://www.friendlyelec.com/index.php?route=product/product... https://www.armbian.com/nanopi-duo-2/ https://www.armbian.com/nanopi-duo-2/ Then all video can be collected by applications like Shinobi, Zoneminder, Frigate, etc. https://zoneminder.com/ https://zoneminder.com/ https://moeiscool.github.io/Shinobi/ https://moeiscool.github.io/Shinobi/ https://frigate.video/ https://frigate.video/ The hardest part would probably be making an enclosure that is solid enough to withstand being exposed to sun, rain, temperature deltas etc. and remain sealed to protect the electronics.