How do I turn my Nokia 635 display off during a phonecall?

[Windows Central Question]

During a phonecall, the screen on my Nokia 635 remains turned on for most of the call. This decreases battery life and is generally annoying, particularly in the dark when I don't want my ugly face lit up and scaring others away. How can I turn off my 635 display while on a phonecall?

 

[RumoredNow]

Unfortunately, Lumia 635 has no proximity sensor. It's supposed to use the Accelerometer to recognize that the phone is against your ear.

Try these two things:
* Set the screen to time out sooner (Settings > lock screen > "Screen times out after" dropdown list
* When on a call try to remain conscious of good upright posture with the handset as this is the clue to the Accelerometer

You may also benefit from Using Gestures Beta https://www.windowsphone.com/en-us/store/app/gestures-beta/38384829-0b39-4f21-a954-d2d4f8a4ac96 However, I don;t recall if it allows 635 to "Answer a call by picking up your phone and putting it to you ear." That certainly would help the phone realize you are on a call.