Smartphones allow Google to track what users are doing at all times

Android phones can report all physical activities of users to Google and the apps used, The Independent reported.

The sensors in the phones monitor, understand and disclose users' real-world movements, on the basis of what is happening to the phone itself.

Phones can tell for instance, if one was standing up or users had just lifted their phone off a desk, or if they had started walking.

An Android permission called ''Activity Recognition'', which was discussed on Reddit and highlighted in a Twitter message by a person with twitter handle DuckDuckGo last week, makes it much easier for developers to work out what users are doing at any one time.

According to commentators, though Activity Recognition is not new, from the reaction to the Reddit and DuckDuckGo posts it seems lot of users are not aware of it.

''The Activity Recognition API is built on top of the sensors available in a device,'' says Google.

''Device sensors provide insights into what users are currently doing. However, with dozens of signals from multiple sensors and slight variations in how people do things, detecting what users are doing is not easy.

''The Activity Recognition API automatically detects activities by periodically reading short bursts of sensor data and processing them using machine learning models.''