TUTORIAL: Taster abfragen
Mit folgendem Programm kann die LED auf dem Mercury-Node mit der Taste an D3 an- und wieder ausgeschaltet werden.
// **
// * LED on/off Flip-Flop
// * Demonstration of digital input and digital output
// * Press the button to switch the led on.
// * Press the button again to switch the led off.
// **
// set port numbers:
const int button = 3; // the number of the pushbutton D3 (hardware-pin SV1:4)
const int led = 4; // the number of the LED D4 (hardware-pin SV1:5)
void setup() {
// initialize the LED pin as an digital output:
pinMode(led, OUTPUT);
digitalWrite(led, HIGH); // switch led off
// initialize the pushbutton pin as an digital input:
pinMode(button, INPUT);
}
// predefine variables
int buttonState = 0; // variable for reading the pushbutton status (0: not pressed, 1: pressed)
int lastButtonState = 0; // variable for storing the last state of the button
int ledState = 0; // variable for status off the led (0: off, 1: on)
void loop(){
// read the state of the pushbutton value:
buttonState = digitalRead(button);
// check if buttonState has changed
if (buttonState != lastButtonState) {
// check if the button is pressed
if (buttonState == HIGH) {
// check if the led is off
if (ledState == 0) {
digitalWrite(led, LOW); // switch led on
ledState = 1; // store ledState
} else {
digitalWrite(led, HIGH); // switch led off
ledState = 0; // store ledState
} // end if else
} // end if
} // end if
// store buttonState for the next programm cycle
lastButtonState = buttonState;
} // end loop
