title: Raspberry PI3 Windows 10 IoT Core Turn HDMI screen off when no activity
body: <p>We have a PI 3 running a UWP app in our company. There is no mouse or keyboard connected. There is a touch screen connected to the HDMI output.
  Is there a way the screen can be turned off automatically when there is no activity for a specified amount of time?
  I used hdmi_blanking=1 in the config.txt but that doesn't seem to do anything.</p>