Hello i'm just working on little documentation of this project 

...but meanwhile, I just got little distracted and just made a quick video on which i tested some standard relay module which you can get from ebay, also example of app usage can be seen there ;)

sorry for not so good focusing I defnitelly need improve on video making skills ;)

above link to such module:

https://www.ebay.com/itm/5V-12V-24V-30A-Optocoupler-Isolation-Relay-Board-Module-High-Low-Trigger/122983016897?hash=item1ca25be9c1:m:mOE1n7OED3Zr9H36cBiEMlg