Virtual Pins and Super Charts - Not so easy for a noob

Solved
3

Why BLYNK_WRITE(V4) subrutine contain digitalWrite? What you are tryin to is read hardware pin and write virtual pin. Try to remove digitalWrite commands there. And also on myTimerEvent() try
sensorData = !digitalRead(0);

void myTimerEvent()
{
  sensorData = !digitalRead(0);    //Read the value of digital pin 0
  Blynk.virtualWrite(V4, sensorData); //Send the value of sensorData to Virtual pin 4
  Serial.print("Pin 0 value = "); //Print "Pin 0 value ="
  Serial.println(sensorData); //Print the value thats in the sensorData variable
  Serial.println(param.asInt(4)); //print the value of virtual pin 4
 }

and

BLYNK_WRITE(V4)
{

}