When the pushbutton is open (unpressed) there is no connection between the two legs of the pushbutton, so the pin is connected to ground (through the pull-down resistor) and we read a LOW. When the button is closed (pressed), it makes a connection between its two legs, connecting the...
instead of pulling a pin to a high value, such resistors pull the pin to a low valued instead. Though being less commonly used, a pull-down resistor is still a valid option.
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 n...
// make the pushbutton's pin an input: pinMode(pushButton, INPUT); } // the loop routine runs over and over again forever: void loop() { // read the input pin: int buttonState = digitalRead(pushButton); // print out the state of the button: Serial.println(buttonState); delay(1...
Pull down resistor This is another option you can choose, which is also a quite popular one: add a pull down resistor. Thus, the default button’s state will be LOW, and when you press it it will become HIGH. Contrary to the pull up resistor, you can’t set this up with just the...
Connecting the resistor to GND sets the push-button’s state to LOW (0). The resistor is known as a pull-down resistor. On the other hand, it would be a pull-up resistor if it was connected to the power supply. This would set the initial state to HIGH (1). To be sure our conn...
* A push button switch is connected to pin five, with a 10K pull-down resistor. * A resistive sensor is connected to analog pin zero, with a 10K pull-down resistor. * The only connection to the RaspberryPi is the USB cable.
//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 ...
turning on the pullups saves having to hook up resistors to the A & B channel outputs */#defineencoder0PinA 2#defineencoder0PinB 4volatileunsignedintencoder0Pos =0;voidsetup(){ pinMode(encoder0PinA, INPUT); digitalWrite(encoder0PinA, HIGH);// turn on pullup resistorpinMode(encoder0PinB...
When the pushbutton is open (undressed) there is no connection between the two legs of the pushbutton, so the pin is connected to ground (through the pull-down resistor) and we read a LOW. When the button is closed (pressed), it makes a connection between its two legs, connecting the...