6m old going into her own room

My daughter is about to be 6m old and can move out of the bassinet and into her crib. I’m worried that I won’t hear her if she’s not in the room with me. Usually she’ll wake up and babble to herself and make random noises and it’s enough to wake me up but it takes a while for her to cry in the morning.

Is everyone using old school monitors?

We have the Nanit but is there another alert other than Apple Watch buzzing? I won’t wake up to a single short alert.