Google is releasing updates to some of its apps following the announcements made at Google I/O 2014. Among it, Google Search update brings in a lot of new features and improvements. The most exciting one being the “OK Google” hot word detection which now works on any screen. That includes Lockscreen and when you’re charging your phone!
You have to enable the hot word detection from the settings [Google Now > Settings > Voice > OK Google Detection] . And you’ll have to train Google Now with your voice three times first. The hot word detection also works on Lockscreen, which is pretty useful sometimes. However, you’ve an option to disable detection in lock screen, if you don’t want it.
This update is rolling out gradually, and as noted by Android Police, the “Ok Google” on any screen option seems to be account specific. You may not have this feature enabled for your device right now. If you don’t want to wait for the update to begin rolling out in your region, you can grab the latest Google Search APK v3.5.14 from the link below and install it normally like you’d install any other APK file.
Download Google Search APK v3.5.14 → download link.
For help on installing APK file, head on over here → How to Install APK files on Android.