What hardware to flow a trashcan at the curb?

[Gerard]

Scenario: two trashcans in the shed, wifi available, no zigbee nor z-wave coverage (I think). There are ways to remind us the trashcan needs to be at the curb to be emptied and either me or the misses will take care of it. And, after being emptied, either me or the misses will roll it back in the shed. Now, what I would like to flow is that a certain trashcan is not back in the shed, which prevents me or the misses to check all the trashcans at the curb only to find out that one of us already rolled it back inside. What hardware would allow me to track these containers to be outside the shed (and presumably at the curb)? So far I only came up with a dedicated bridge in the shed and contact switches with magnets but that seems silly and costly. There surely must be a better way. Anyone?