 <p>Actually the work of proximity is to detect other devices like windows phone , or windows computer through NFC.It detect those devices which has NFC tags</p> <p>Here is the link for your reference <a href="https://msdn.microsoft.com/library/windows/apps/jj207060(v=vs.105).aspx#BKMK_Requiredcapabilities" rel="nofollow">https://msdn.microsoft.com/library/windows/apps/jj207060(v=vs.105).aspx#BKMK_Requiredcapabilities</a></p> <p>and there is no clear explanation on any of the website about the detection of human body or any object that comes near the phone like when the screen turns off while getting it near to our ears may be we can use light sensors to detect object nearby.</p> <p>I think that this sensor does not have a API and is provided by default by windows phone API if we use the calling API classes</p>