Humax do an internal security camera that is actually Ycam I believe. Although meant for use with a smart phone, they say it also works with the more recent humax stb's.
Also, you get cloud access without payment (AFAIK).
You can stick the camera in the fron window or an upstairs window to watch outside goings-on. I think the app that runs on the stb, fetches the data saved on the cloud.
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