Withings' $300 Aura is a device that monitors your sleep, helping you determine if you sleep too little or too much. The Aura also offers sleep programs, with colored lights and sounds to help you fall asleep, and to help you wake up when you are in a light sleep phase. Withings claims that the reddish light the device emits before you go to sleep encourages your body to create melatonin, which helps you fall asleep. Conversely, the bluish light it emits while waking you inhibits melatonin, increasing your alertness.
The Aura comes in two parts. The sleep sensor is a flat, cloth-covered device that you place under your mattress. This connects to the bedside device, which is about 11 inches tall, and looks like a ship's ventilation funnel. The bedside device has a speaker, a digital clock, and USB ports at the back; you can plug your iPhone into one to charge it). Its round "face" emits LED light in a variety of colors that sync with the Aura's sleep programs. You swipe its side, or tap it on the top, to start or end programs, or to turn its light on or off. (It has a reddish light--different from the red light used as a sleep enhancer--that you could use as a reading lamp.)
Rest test
I've been using the Withings Aura for about two months. I typically don't have any trouble sleeping, so I didn't find the sleep programs very useful--I only ended up using them a few times. The wake-up sound is jarring and sudden rather than starting at a low volume and increasing as you become awake, and the white noise, which is supposed to help you go to sleep, is just a distraction. But I live in a rural area, and don't have traffic outside my window. If you live in a city, these sleep programs might be what you need.
The device connects via Wi-Fi, sending data to your Withings account, which you can access on the web, or via an iOS app (an Android app is in the works). You can view this data for any individual day to see how you sleep. It records the amount of time you sleep, periods when you are awake, and when you are in the three different levels of sleep: light sleep, deep sleep, and REM sleep. However, it sometimes conflates two days of sleep.
You can also view a more succinct weekly overview of your sleep activity. This summarizes the information in the daily view, and also includes your daily activity via your Withings activity tracker or the Withings Health iOS app if you have an iPhone 5S, 6, or 6 Plus, which can record your movement with the M7 or M8 coprocessor. It also integrates with Apple's HealthKit, but data in the Health app is useless--it only shows total sleep time.
The Aura's sleep sensor detects any presence in bed, not just when you're sleeping. You may just be lying in bed reading--the Aura recorded me doing that for about 25 minutes in the afternoon. Another thing to note: I found that when my cat Titus lies on the bed near the sleep sensor, the Aura thinks it's me, and counts his presence as sleep, too. So, a lot of "sleep" was recorded for times when I was actually awake.
I was skeptical about one of the features that Withings touts: that the Aura can record your heart rate while you sleep. But this actually works. It detects the micro-movements of your body as your heart beats, and records this. A Withings representative explained that this has no real value (other than for people with a very specific heart condition), but that they present the data because it can be recorded, and because customers requested it.
The problem with the Withings Aura is that it doesn't tell you much, and only if you actually look at the app or Withings' website. If you don't sleep well, you probably already know that; if you sleep nine hours or more, you also know that, and you probably feel a little better. As I wrote recently, this type of device needs to do more than just present raw data.
Some iOS apps give your sleep an efficiency rating, which can be more useful than just looking at a chart with different colors, and a percentage relative to an 8-hour sleep session. Such a rating can tell you that, while you may have slept eight hours, you were restless--maybe you shouldn't have watched all those episodes of American Horror Story.
Bottom line
As with many such devices that track health metrics, the Aura is interesting, but its data isn't very helpful. Tracking any activity metric is good, but having actionable advice would be better. Also, the fact that it detects any presence in bed--by me or my cat--and not just sleep, makes the device's data unreliable. The Withings Aura is a good piece of technology, but it needs to get some kinks worked out for it to be useful.