Vibrate along with the ringtone feature in Android devices plays an important role when the Android user is working in the noisy environment. When a call is received, either ringtone or vibrate or both may inform the Android users about the coming call. If a user cannot listen the sound of ringtone due to noisy environment, she / he may feel the vibration of the Android informing her / him about the incoming call. Android has a feature, which when applied, can enable either of these to inform about the incoming call:
- Ringtone Sound
- Vibrate
- Ringtone + Vibrate
- None
You may select any of the above mentioned features to inform Android users about the incoming call but if you feel any need, feel free to see the instructions.
Instructions
1: Tap the icon of the ‘Phone Dialer’ app on the Home screen of your Android 5.1 Lollipop devices to open up the ‘Phone Dialer’ app screen.
2: At the ‘Phone Dialer’ screen, tap the settings button, placed on the top right corner of the screen. It will open up a popup menu.
3: Tap the ‘Settings’ in the popup menu.
4: Tap the ‘General’ at the ‘Settings’ screen. 
5: At the ‘General’ screen, see ‘Also vibrate for calls’ in the ‘Sounds and vibrate’ section is not checked, i.e. not enabled.
6: If you want to enable the vibrate feature along with ringtones, tap the ‘Also vibrate for calls’ to check and enable. 
Now, upon receiving the incoming call, the user will listen not only the sound of ringtone but also feel the vibration of Android device.
That’s all!