Google 's 'on-body detection ' users the phone 's accelerometer to know when it 's being moved and will only lock when placed on a flat surface . Google has already experimented with unlocking phones using faces , but for some this just is n't immediate enough . A number of Android owners have spotted a new feature that keeps the phone constantly unlocked as long as it 's in a person 's hand , resting on their leg or even just sitting in a pocket . The 'on-body detection ' feature uses the phone 's built-in accelerometer to know when it 's being handled or moved , and will only lock the screen when placed on a flat surface . On-body detection was first spotted by fan site Android Police in the Smart Lock menu of a Nexus 4 running Android Lollipop . But there have since been numerous reports of the phone appearing on other Lollipop devices , and not just Google 's own Nexus range . It appears to be linked to the most recent version of Play Services - a tool used to update Google 's built-in apps . The on-body detection menu explained : 'The feature uses your device 's accelerometer to detect whether your device is still being carried on the body . 'If your device detects that it 's no longer being held , your device wo n't stay unlocked . ' The phone has to be unlocked the first time it is picked up in the morning but once unlocked it will stay open until it is put on a table or similar . But as Google added , if the user unlocks their device and hands it to someone else the phone or tablet stays unlocked as long as the other person continues to carry it . It is also unclear how active the screen will be in a pocket . Google may shut down services but keep the screen unlocked , to avoid opening apps or accidentally calling people , known colloquially as 'butt dialling . ' Google offers passwords and PINs to secure its phone , and more recently added Face Unlock ( pictured ) to phones running Android Ice Cream Sandwich and above . It recognises a person ’ s face and can establish whether or not the face being shown to the camera is real , or is a photograph . These services may then be enabled once the phone detects it is in a person 's hand . It is also not clear what impact having the screen constantly unlocked will have on battery life . MailOnline has contacted Google for more information . A combination of special hardware and software will be used to accurately verify it is you , not a picture of you or someone trying to impersonate you . The cameras use infrared technology to identify your face or iris and can recognize you in a variety of lighting conditions . These security features are opt-in , meaning that users will be able to still rely on passwords and PINs to unlock devices and features if they so desire . Google offers passwords and PINs to secure its phone , and more recently added Face Unlock to phones running Android Ice Cream Sandwich and above . It recognises a person ’ s face and can establish whether or not the face being shown to the camera is real , or is a photograph . On-body detection is the latest feature hoping to remove the need to enter security details regularly . Last week Microsoft said devices running its Windows 10 software , which launches later this year , can be unlocked by looking at them , or using a fingerprint reader . Apple made the fingerprint reader , or Touch ID , mainstream on its iPhone 5S and Samsung added a reader on its Galaxy S5 . Microsoft 's version is called Windows Hello , it will be part of Windows 10 when it launches later this year . These security features are opt-in , meaning users will be able to still rely on passwords and PINs to unlock devices and features if they desire . On-body detection is the latest feature hoping to remove the need to enter security details regularly . Last week Microsoft said devices running its Windows 10 software , which launches later this year , can be unlocked by looking at them ( pictured ) , or using a fingerprint reader . Called Microsoft Hello , The firm is so confident the system ca n't be fooled and has even tested users holding up pictures of others . These security features are opt-in , meaning that users will be able to still rely on passwords and PINs to unlock devices and features if they so desire .
Feature was first spotted by fan site Android Police on a Nexus 4 . Option appeared in the Smart Lock security menu on Lollipop . Once a phone is unlocked , the screen remains 'open ' while it 's being held . It also uses the phone 's accelerometer to remain unlocked even in a pocket . Google has n't confirmed feature but it 's been spotted on multiple devices . It is unclear if screen could be accidentally used to call people , for example .