C/C++ Program to blink an LED WITHOUT Arduino, WITHOUT Microcontroller

1. You will need a 470 ohm resistor, an LED of any color and an FTDI USB to serial module. We have tested the program on Windows 10 - no drivers were required. Please refer the appended video for all the details.
2. Compile the program using visual studio - any version will be OK.
3. Assemble the circuit on a bread-board or on a PCB and plug it ON.
4. The COM port number can be obtained from the device manager.
5. Run the program!

The source code

This is the program with all necessary comments -

#include <iostream>

#include <windows.h>

using namespace std;

// COMPILE WITH A WINDOWS COMPILER 
// SUCH AS VISUAL STUDIO C++ 2005 
// OR LATER. PROGRAM TESTED ON 
// WINDOWS 10, 8 and 7 
#define ON  SETDTR

#define OFF CLRDTR

int main()
{

  // see the video below on how to 
  // get the port number from 
  // device manager 
  printf("COM Port number[1-9]: ");

  // path format \.\COM1 
  char path[] = "\\.\\COMx";

  cin >> path[6];

  HANDLE hComm = CreateFileA(
  path,
  GENERIC_READ | GENERIC_WRITE,
  0,
  0,
  OPEN_EXISTING,
  NULL,
  0);

  if (hComm == INVALID_HANDLE_VALUE)
  {

    printf("Error. Check COM Port?");

    return -1;

  }

  // user input key 
  char key = 0;

  // state of the LED 
  int state = OFF;

  do 
  {

    // toggle the state of the LED 
    state = (ON == state) ? OFF : ON;

    // turn the DTR high/low 
    EscapeCommFunction(hComm, state);

    // ask the user to enter 
    // any key to toggle state 
    // q to quit 
    cout << "Enter any key to";

    cout << " toggle LED [q to quit]:";

    cin >> key;

    cout << "LED turned ";

    cout << (ON == state ? "ON":"OFF");

    cout << endl;

  } while ('q' != key);

  // close the COM handle 
  CloseHandle(hComm);

  return 0;

}

Circuit diagram and Discussion

Please refer the video below for discussion and circuit diagram -