Acrob004

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Pushbutton

To test the pushbutton, please connect one LED with current limiting resistor together with a pushbutton:

This setup doesn't require microcontroller, it is just to test it and recognize its function, pinout and operation. No program required!

Let's modify the circuit and try to measure the input with the microcontroller and display its value on the terminal. Modify the connection according the following diagram and download the attached piece of software.

#define SWITCH 3                 // select the pin for Switch

void setup()
{
 Serial.begin(9600);
 pinMode(SWITCH, INPUT );        // this pin is an INPUT
 Serial.println("Button test:");
}

void loop()                      // endless loop
{
 Serial.print("Input D3 = ");
 Serial.println(digitalRead(SWITCH),BIN);
 delay(250);                     // wait 1/4s for another
}

Another example uses the switch to control the LED. Exactly as in the first experiment, but now the controller makes the decision.

#define SWITCH  3                // select the pin for Switch
#define LED_Green 7              // select the pin for LED

int State = 0;                   // variable to store the pushbutton value

void setup()
{
 pinMode(LED_Green, OUTPUT );      // this pin is an OUTPUT
 pinMode(SWITCH, INPUT );        // this pin is an INPUT
}

void loop()                      // endless loop
{
 State =  digitalRead(SWITCH);
 if (State = HIGH )             // notice 2x = !!!
   digitalWrite(LED_Green, HIGH);    // make it visible
 else
   digitalWrite(LED_Green, LOW);     // turn off
 delay(250);                     // wait 1/4s for another
}

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