MAS3:
Research 'protection diode', using search function.
thank you very much vor the advice. and this is more constructive posting on a colaboration thread 
i'll look into it ASAP and modify the relay board.
retrolefty:
It's as if you don't yet know how to drive a car but your project is to build a formula one race car and enter a race. And asking for help with this specific project is bound to give you advice that you won't understand and in many cases will not be the help you actually need.Sorry, but my advice is to lower your expectations and learn to walk before you run.
didn't you read any of my posts? i'm sure you'll find there somewhere mention of the use of the examples from the Arduino IDE.
oh by the way, thank you for taking your time and posting on this thread.
firstly, i didn't know that this page is used to procure people/solutions. sorry, another of my mistakes.
and secondly, whatever you call it (formula 1) or just a driving... - didn't you read that the project is finished?