It has been working since the day I got it about a month ago but it stopped working today. it just stopped working for no reason. Nothing changed. No new hardware. No changes to anything on my part. when I look at the display nothing happens, it doesn't acknowledge my presence. it is like the feature is turned off but when I go to the app it shows that it is enabled. It is behaving the same way for my wife. I can only assume that it is another failed update from Google.
