Connecting two arduinos for seperate purposes

Using Arduino Project Guidance
#1

For my 4th year project, we have an ECG heart rate monitor so the sensors are connected to a front end circuit, then the circuit is connected to the Arduino that transfers the data to a mobile phone app (android) which transfers the data to a cloud.

Ideally we wanted to use one Arduino to control everything but this is not possible. After some research I found that the Adafruit RGB LCD is not compatible with the Arduino Due.

Is there a way to connect two arduinos together so that the Arduino Uno controls the LCD and the Arduino Due controls the data transfer and receive?

The LCD has a simple menu woth two options that controls whether or not data is being accepted to the Arduino Due.

#2

You can have them talk to eachother over serial, or make one of them an I2C slave...

But I'd be inclined to just get a LCD that works with the Due...

#3

Do you know of any LCD shields that are similar to the Adafruit RGB LCD that are compatible with the Due?

Also, how can I make one an I2C slave?

#4

use arduino yun, it can post directly to the cloud

#5