It's not just him who listens to you. Google / Motorola
If you have a device running with Android 4.1 or higher, you can install the app Open mic +, which start listening to your commands like Moto X's factory software. Using the app is very easy. It comes configured with the initial Ok Google Express, which can be changed later. With it, you activate your smartphone by voice, as well as perform searches, record messages, and many other functions. Some of them work even offline. The only downside (as in the case of Active Notifications) is the increased battery consumption, which can otherwise be controlled in the settings, not letting the app run in the background all the time.

The Mic + interface and voice controls. / Lifehacker
Open Mic + free has no ads and can be downloaded from the Play Store.
If you already downloaded it, how did it work on your device? Tell us your impressions.
. (tagsToTranslate) Moto X (t) Voice Control (t) App (t) App (t) Mic + (t) Touchless