We want to accomplish that the Arduino reacts to presses on a TFT screen when a particular picture is displayed on the screen. The screen is installed on top of the Arduino.
We think that this picture will help in understanding the set-up.
When the Arduino detects a press, it should activate the motor (yellow, left in the picture).
Can this be achieved with one Arduino?
The thing is that no plug-in location is free in the Arduino after we plug in the TFT screen.
Therefore, we are using a second Arduino for controlling the motor.
However, we are wondering if it is possible to carry out our project with only one Arduino.
If this is not the case, how is it possible that two Arduinos communicate with each other?
Sofie_and_Alex:
The thing is that no plug-in location is free in the Arduino after we plug in the TFT screen.
Therefore, we are using a second Arduino for controlling the motor.
How is your first Arduino telling the second one to operate the motor?
Also, please post a link to the datasheet for the TFT screen you are using
It looks as if the shield uses all the Uno pins except 0 and 1 and A5 and even those pins are not easily accessed when the shield is attached.
It seems that it can work with a Mega and that is probably the simplest solution as it will have lots of accessible unused I/O pins. And you probably won't need a second Arduino if you use a Mega.
Sofie_and_Alex:
There is no way around this problem except buying a Mega?
It seems as if the screen and its SD Card reader both use SPI for communication. SPI can connect to multiple devices so if you can find a method to connect to the SPI pins Mosi Miso and Sclk and to A5 (to use as Chip select) then it should be possible to connect to the other Arduino using SPI.
Another option, if you can access pins 0, 1 and GND would be to use Serial for a connection to the other Arduino. However you would probably need to disconnect from the other Arduino when uploading a program to the Arduino with the screen.
For the amount of trouble involved in either of those I would consider a Mega clone to be a better value alternative.