| /* | |
| Input Pull-up 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 Mar 2012 | |
| by Scott Fitzgerald | |
| This example code is in the public domain. | |
| https://www.arduino.cc/en/Tutorial/BuiltInExamples/InputPullupSerial | |
| */ | |
| void setup() { | |
| //start serial connection | |
| Serial.begin(9600); | |
| //configure pin 2 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 pull-up 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); | |
| } | |
| } | |