Synchronize linear stage with sensors via Ardunio Due

Hi folks,

I have a problem with my project. I hope you could help me with it. My knowledge in electronic is rather limited. Full details of the problems are described below.

My problem is

_ I have linear stage that can be connected to PC via USB ports and controlled via an open source software based on Microsoft.Net languages. I have sensors that can be triggered via TTL level signals (Vmax = 5V).

_ I want the sensors to start measuring at the same time as when the stage starts moving or with a fixed delay (to avoid the acceleration).

My thought for this problem is

_ I will connect the stage and the Arduino Due (Native Port) to USB ports of the PC.

_ With the control software, I can initialize the communication between the PC and the stage and the Arduino.

_ Commands to move the stage will be sent to both ports.

_ When the Arduino receives signals from the PC via the USB port (probably Rx line), it will switch an I/O pin to "high" and this signal will be sent to the sensors for triggering.

May I know how to make the Arduino respond when the data is transmitted via USB port?

Thank you very much for your help.