Need some kind of wireless beam type alarm. My Mother has cancer-not doing well..Don"t need to/not able to get up by herself but sometimes does..Dad has to sleep in another room because he snores so bad--noone sleeps in same room with him. Thought about and looked at things like driveway alert, but not sure the chime type is loud enough to wake my Dad up and I"m thinking the infared transmitter might transmit too wide a beam----anyway need something that shoots straight beam that if broken by Mom trying to leave her room, would alert him in the room next to hers.He is hard of hearing so needs to be more than a chime. Any thoughts? Thanks