Hi. I have a doubt about if i should use a pullup resistor, when using the Default Button Exemple Code from Arduino IDE. The idea is: to leave the pin13 LED ON and turn it off when i push the button. I wired as the pictures attached, both gave me the same result. But in the second one, i removed t…

As LarryD says the resistor should keep pin 2 pulled up to 5v when the button is not pushed otherwise it can float ( read either high or low at any time) . Arduino has a built in pull up resistor on all I/o pins that can be activated by using INPUT_PULLUP So the resistor is not really necessary .

I just copied the circuit on the Button Tutorial at Arduino.cc, the i wired GND and VCC on the opposite way to make the LED stays ON and turn OFF only the button is pressed. But okay, i'll remake the circuit. Only question: WHY!? I'm attaching a picture just to make sure. Is it correct? [model_3…

Model 2 will work if you use INPUT_PULLUP. Model 1 will never work because it is wired improperly - the two pins each side of the switch are internally connected. That means that either: the pullup is trying to pull up the side of the switch that is grounded; the pullup would need to go to the side…

The way the "Button" example is written pushing the button will drive pin 2 high. Here's what it says in the sketch: The circuit: * LED attached from pin 13 to ground * pushbutton attached to pin 2 from +5V * 10K resistor attached to pin 2 from ground * Note: on most Arduinos there is already…

i wired GND and VCC on the opposite way to make the LED stays ON and turn OFF only the button is pressed. You don't need to reverse the hardware. You can reverse the logic in your software sketch. :wink: You can use a pull-up or a pull-down resistor as long as the switch "pulls" in the opposite …

Aaahh...i think the Circuit image made with Fritzing in this page https://www.arduino.cc/en/tutorial/button is wrong, because the schematics shows exactly what Hutkikz, DrAzzy and jboyton said. Thanks guys! DVDdoug: You don't need to reverse the hardware. You can reverse the logic in your softwar…

You may find Mr. Gammon's discussion helpful: Gammon Forum : Electronics : Microprocessors : Switches tutorial Gammon Forum : Electronics : Microprocessors : Switches tutorial

LarryD: You may find Mr. Gammon's discussion helpful: Gammon Forum : Electronics : Microprocessors : Switches tutorial Thanks for the link! Thinks are pretty clear now :wink:

Pushbutton and Pull-Up Resistor

Projects General Guidance

LarryD July 17, 2015, 9:34pm 2

Not wired properly.
The resistor should be on the blue wire (pin 2) then to +5V.

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Pushbutton and Pull-Up Resistor

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