Help me please with V-REP sensors!

Hello!

File : I’m new in V- REP and I was created the small project with conveyor and robot. But I want robot will start painting after a sensor turn it , but NOT at once after Start simulation. Can anybody help me with it?

File link: https://drive.google.com/file/d/1Wp2ItKT4P88fOqgQRo44YUhUUcPD_f5J/view

Thank You!