| /* |
| Input Pullup Serial |
| |
| This example demonstrates the use of pinMode(INPUT_PULLUP). It reads a |
| digital input on pin 2 and prints the results to the serial monitor. |
| |
| The circuit: |
| * Momentary switch attached from pin 2 to ground |
| * Built-in LED on pin 13 |
| |
| Unlike pinMode(INPUT), there is no pull-down resistor necessary. An internal |
| 20K-ohm resistor is pulled to 5V. This configuration causes the input to |
| read HIGH when the switch is open, and LOW when it is closed. |
| |
| created 14 March 2012 |
| by Scott Fitzgerald |
| |
| http://www.arduino.cc/en/Tutorial/InputPullupSerial |
| |
| This example code is in the public domain |
| |
| */ |
| |
| void setup(){ |
| //start serial connection |
| Serial.begin(9600); |
| //configure pin2 as an input and enable the internal pull-up resistor |
| pinMode(2, INPUT_PULLUP); |
| pinMode(13, OUTPUT); |
| |
| } |
| |
| void loop(){ |
| //read the pushbutton value into a variable |
| int sensorVal = digitalRead(2); |
| //print out the value of the pushbutton |
| Serial.println(sensorVal); |
| |
| // Keep in mind the pullup means the pushbutton's |
| // logic is inverted. It goes HIGH when it's open, |
| // and LOW when it's pressed. Turn on pin 13 when the |
| // button's pressed, and off when it's not: |
| if (sensorVal == HIGH) { |
| digitalWrite(13, LOW); |
| } |
| else { |
| digitalWrite(13, HIGH); |
| } |
| } |
| |
| |
| |