by Raju Purohit
This is a simple flow which measures speed in kmph using GPS and displays in notification. Its accuracy depends on GPS accuracy but my experiments have shown the readings are very accurate.
Root is required since I've used GPS enable & disable blocks.
If you are using non-rooted device, just remove 4 of those Location enable/disable blocks and it'll be good to go.
Make sure only GPS sensor mode is enabled, and not battery saving mode, since it doesn't measure speed. It'll only show 0 kmph all the time.