Hello,
The project is easy and I have experience with .NET and Arduino connection before.
Regarding the price it's 40 USD, when you accept the job as complete.
Regarding testing: I have several Arduino boards, and I can make a complete testing with the board you plan to use. Of course the test setup from my side will be tested for at least 2 times the time you need the end device to run.
I hope this is what you are looking for, if not I am ready to change my offer and/or preposition.
Hope to hear from you soon,
Mihail Vrachanski