Introduction: Make a Pushbutton Without a Resistor

Need a pushbutton but don't have any resistors?

Using Arduino, 2 wires, one pushbutton, and one led, and Arduino, turn on and off an LED (or anything else you decide to turn on and off).



Instead of using the typical button schematic using a pullup or pushdown resistor, like the Fritzing image, here's a way to get around that, using Arduino, and declaring the button pin as a digital input, but then writing HIGH to that digital input pin. 

In the setup function:
pinMode(buttonPin, INPUT); 
digitalWrite(buttonPin, HIGH);
LED from pin 13 to ground

Wire it like the schematic in the photograph: 
Arduino pin 2 to the button pin. 
the other side of the button is wired directly to ground. 

Upload the following code:

Comments

author
Radioactive_Legos made it!(author)2012-08-08

A simpler way of enabling the internal pull-up resistor is to replace this: pinMode(buttonPin, INPUT);
digitalWrite(buttonPin, HIGH);

with this:
pinMode(buttonPin, INPUT_PULLUP);

author
frank26080115 made it!(author)2012-07-31

your code comment "initialize the buttonPin as output" is wrong, you are actually enabling the internal pull-up resistor for that pin.

author
frank26080115 made it!(author)2012-07-31

your code comment "initialize the buttonPin as output" is wrong, you are actually enabling the internal pull-up resistor for that pin.