Hi, I have come across a cool little trick that can be done with an Android phone. First off, it must be rooted in order to do this. For the longest time, I have wanted to be able to use my phone in my car by just yelling out "Ok Google" and having it work for me. I looked into trying to do this with the steering wheel controls, but it would not natively do this. Users with the Moto X can do this as part of their phone's Auto mode, but other phones do not do this natively. I have found a solution that works for me. It gives me the ability to put the phone in the dock and simply call out "Ok Google" whenever I want...its really cool. I am using a Galaxy S4, running 4.4.2, your mileage may vary depending on what type of Android phone you use.
1. Phone must be rooted.
2. Install Xposed Framework application, (Just google it, not hard to find)
3. Install module named, "Ok Google for 3rd Party Activities"
4. Download and install CarHome Ultra Application.
5. Go into settings for "Ok Google for 3rd Party Activities" module and set the module to work with Carhome Ultra on "All activities"
6. Reboot phone for good measure.
Once done, test by putting phone in car dock or triggering car dock mode on phone, choosing CarHome Ultra as the default application. If everything work right, the phone sits active in the dock and you should be able to call out "Ok Google" whenever you want.