I used beddit (https://www.beddit.com/) a lot, but since they were bought by apple there is not really any updates for app or hardware. It works like withings sleep where you don‘t wear anything, but it needs Bluetooth connection to your phone the whole night because it doesn’t have any storage.

So I am not really statisfied with it. The app runs on the phone the whole night and drains the battery, no smarthome features are built in and there is always bluetooth sending data.