All this talk about what constitutes a fall misses the point that OP simply, if I read it correctly, wants to send data from the sensor to a C# application. Seeing what code you have now, OP, is going to be essential. Are you correctly reading data from the sensor? How do you know? The only way to really know is to send data to the serial port, where some application on the PC is listening. One such application is the Serial Monitor. Another is your C# application.
If you can send data to the Serial Monitor, you can send it to your C# application.