Hello,
I have over 8 years of experience with microcontrollers and C programming and I've been working with Arduino for past 3 years. I have a lot of experience with it and the taks you are describing sound very easy to me.
As I am new freelancer, I will do it for free, because I need reputation. Please, asign me this task, you will not be dissapointed.
Regards,
Blaž Mandl