Smartphone notifications are a perennial problem, especially when you're busy doing something else, like walking or driving. The developer team of Paranoid Android believe they have one solution with their new Peek feature, which will allow users to quickly glance at those notifications without having to unlock their device or employ sometimes awkward systems like TTS (text-to-speech).
There are two parts to Peek. The first starts inside the device with the sensors, which Peek utilizes to determine activity only when the screen is off. When the screen is on, Peek doesn't poll the sensors so it doesn't incur unnecessary clock cycles. Peek uses two sensors in particular, the gyroscope or the proximity sensor, but never both at the same time. If the gyroscope determines that the phone is on a table, Peek doesn't use the proximity sensor. On the other hand, if the proximity sensor thinks it is in a pocket, the gyroscope is not polled. When a notification is received, Peek wakes up the CPU at a very low frequency to conserve battery while listening to those sensors. If nothing happens within 10 seconds, Peek stops polling the sensors.
It is when the device is picked up or taken out of a pocket within that timeframe does the next part kick in. Peek turns on the screen to display the notification, after which users will be able to view them or interact with them as normal. The video below demonstrates how the notification can be viewed on the lockscreen itself without having to go to the associated app. It seems to behave quite similar to the Moto X Active Display, which is emulated by the third-party Active Notification app. Unfortunately, the battery-saving feature is known to only work with devices using AMOLED screens and is a bit unreliable on anything else.
The Peek feature is already available on the Paranoid Android 4.2 Beta update (thanks Paul Méndez for the tip), so braver souls might be able to test how well it works. I would definitely be nice to see this feature make its way to other devices, even those running stock manufacturer ROMs, though it is more likely that Peek will mostly remain within Paranoid Android's fold.