I need Homekit or low power Bluetooth repeater.

I have a couple of low power Bluetooth Homekit devices (sensors) that are out of reach of my Apple TV and in an unheated/uncooked area (garage attic). Another Apple TV would be an option, BUT, there’s no room for a TV with it, so how could I maintain it? I suppose I could buy another iPad and leave it plugged in 24/7, but that too might need maintenance.