SunFounder R3, Manual

Page: 99 / 527

SunFounder uno-and-mega-kit
Set the input and output status of the pins
pinMode (buttonPin, INPUT ); //initialize thebuttonPin as input
pinMode (ledPin, OUTPUT ); //initialize the led pin as output
We need to know the status of the button in this experiment, so here set the buttonPin as INPUT; to set HIGH/LOW
of the LED, we set LedPin as OUTPUT.
Read the status of the button
buttonState = digitalRead (buttonPin);
buttonPin(Pin12) is a digital pin; here is to read the value of the button and store it in
buttonState
.
digitalRead (Pin) : Reads the value from a specified digital pin, either HIGH or LOW.
Press the button to make the buzzer sound
if (buttonState == HIGH )
{
digitalWrite (ledPin, HIGH ); //turn the led on
}
else
{
digitalWrite (ledPin, LOW ); //turn the led off
}
In this part, when the buttonState is High level, write ledPin as High and the LED will be turned on. As one end of
the button has been connected to 5V and the other end to pin 12, when the button is pressed, pin 12 is 5V (HIGH).
And then determine with the
if (conditional)
; if the conditional is true, then the LED will light up.
else
means that when the if(conditional) is determined as false, run the code in
else
.
6.4 Lesson 4 Doorbell
6.4.1 Introduction
A buzzer is a great tool in your experiments whenever you want to make some sounds. In this lesson, we will learn
how to drive an active buzzer to build a simple doorbell.
6.4. Lesson 4 Doorbell 93