I would like to experiment with 2 LCD's, the first one is the DFrobot LCD keypad shield (16x2) and the second an HD74800-compatible LCD (4x20) connected to an MCP23016 (found on TkkrLab).
I am very new to using the arduine (UNO) and couldn't figure out how to do this (if it is even possible).
Do I have to merge 2 libraris to get it working?
An if so how?
It should be possible as long as there are no pin contentions (which I haven't checked).
You will have to 'include' three libraries to get it working.
<LiquidCrystal.h> for the DFRobot device, and both <IOlcd.h> and <Wire.h> for the I2C device .
You would have to invoke each of the 'lcd' libraries with a different name.
LiquidCrystal lcd1( ... );
IOlcd lcd2;
And then use lcd1 ... when you want to send stuff to the DFRobot device and lcd2 ... when you want to send stuff to the I2C device.