LED Coding with user defined input

[mst920701]

Hi all, my name is Seet Ting and I am new to raspberry pi, matlab and also programming language.

Currently, I am doing a project that need to interface with raspberry pi with Matlab. I have set a threshold for my input in order to blink my LED.

Here i attached one of the data input. The data that I attached is basically a sine wave graph which range from 3000 to 7100uV.

So I have set the threshold voltage to 3000,
which is when V>3000, the LED light should ON, but it doesn't act so. Can anyone please help me in this simple case><