Hi,
I'm an electronic engineer with more than 5 years of experience in Arduino programming. After reading your project and watching the youtube description, I've decided to apply for the project as I have previous experience in using Arduino based car modifications. Actually this seems to be a straigt forward work, we can install an app on your nexus tablet, and communicate with Arduino and tablet via USB OTG cable. So once you touch on buttons, arduino will act accordingly.
According to your current code, it seems that your functions are already working fine. So we can add the Tablet communication for this code easily. Actually, you don't need to send the devices to me, instead, you can do the programming yourself if you need (and save the shipping cost :)) .
I'm confident about completing this project and looking forward to hearing back from you.
Thank you
Anusha