If you are having problems with the Double Tap app, this might help you. This version allows you to specify your own “window of opportunity” for the taps, which is needed due to the extreme lag of the cloud processing. You may also need to tweak your master device to be compatible. Please see my detailed notes in the source code documentation as to what needs to be done to make sure this works.
Hope this helps someone All credit due to the original author @ smartthings, all I did was debug some stuff and make a relatively minor tweak.