snip
I need to have some sort of proximity detector which will either
prevent the door from closing, or alternatively beep at me or flash a
light if the car isn't far enough forward in the garage.

Any ideas, possibly with links?

How about the old tennis ball hanging from the garage roof which touches the
windscreen when the car is far enough in the garage. Not high tech but it
works!
Steve R

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One piece, one button suit, timeless fashion. All made by the same
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