I started with a Pi 4 and RPI HQ camera - and I grabbed a plastic dome and waterproof box.
Over time - it got updated to a Pi 5 with Waveshare combined M.2 Sata/PoE hat - so now it takes power from the network cable and has a more stable disk than an SD card.
A Keogram is an image giving a quick view of the day's activity. For each image a central vertical column 1 pixel wide is extracted. All these columns are then stitched together from left to right. This results in a timeline that reads from dawn to the end of nighttime (the image above only shows nighttime data since daytime images were turned off).
Since the instance I am running has auto-gain enabled there will be some hops in brightness across the keogram.