73bc9136_Review_2013____Webmaster_Facts__Google_Glasses_Component
[Use] This feature is tucked to the inside front panel of the glass and can detect your eye lid movements and response accordingly. [Abuse] Not much sure about it but I have a very bad feeling about some electronic thing pointing at my retina all the time. I guess this feature can lead to defective eye in the long run. [Google Glasses Component] 
Internal Motion sensor
D i s p l a y S c r e e n
E a r p h o n e
M i c r o p h o n e
E x t e r n a l C a m e r a
I n t e r n a l M o t i o n s e n s o r
G l a s s / L e n s
B a t t e r y
T o u c h p a d
Google Glasses - Advantages and Disadvantages (Review 2013) | Webmaster Facts
Google Glasses Component