Your SmartSleep device will work without the phone near it. It is fine to have your phone in a different room charging while you sleep. Your phone is not required to be in proximity to the SmartSleep device to make it work at night while you sleep. The device works independently by itself. You only need your phone turned on, Bluetooth on and app opened when you are syncing your device to the app for the upload of data to see your personal sleep results.