Toggle Sample Data

unsigned long interval = 0;
int toggle = 0, rel = 0;  //Global variables

void setup() {
  pinMode(8, INPUT_PULLUP); //Connect PIN 8 to button to ground
  Serial.begin(9600); //Start serial COM
}

//Sample Data Function
void sampleData(){
  Serial.print("Sample Data: ");
  //Serial.print(<My Accellerometer Data>);
  Serial.print("\n");
}


//Control loop
void loop() {
  int input = !digitalRead(8);  //Check if button is pressed (1 == Pressed 0 == Unpressed)
  if(input){
    if(!rel){  //Release trigger has not been activated so execute toggle
      toggle = !toggle;
      rel = 1;  //Activate release trigger
    }
  } else {
    if(rel){
      rel = 0; //Reset release trigger when button is released
      /*You may execute code here on button release!*/
    }
  }

  //Run sample code when toggle is on ; run at an interval of every 300ms
  if(toggle && millis() - interval > 300){
    interval = millis();
    sampleData();
  }

}