Many years ago, I bought a bed/sleep sensor made by Withings. It worked fantastically, for about a year. Decent sleep measures, circadian aware alarm, all that.

Then it just stopped working. Contacting support thought it might be the pad, and they sent me a replacement. That worked for a while longer, until it didn't. At that point, Withings had been sold to Nokia, and wasn't interested in maintaining their system anymore.

I miss it. I'm sure that this system won't be able to do all the measurements the Withings one did, but thats OK. I've got a watch for that. Def. going to have to try this soon!