Using 4 legs Switch
================================
[sourcecode language=”cpp”]
/*
Oscar’s project
turn LED on and off with a switch
*/
// constants type won’t change (just good practice, can declare without)
// set pin numbers:
const int buttonPin = 1; // the number of the pushbutton pin
const int ledPin = 2; // the number of the LED pin
// variables will change:
int buttonState = 0; // variable for reading the pushbutton status
void setup() {
// initialize the LED pin as an output:
pinMode(ledPin, OUTPUT);
// initialize the pushbutton pin as an input:
pinMode(buttonPin, INPUT);
}
void loop() {
// read the state of the pushbutton value:
buttonState = digitalRead(buttonPin);
// check if the pushbutton is pressed.
// if it is, the buttonState is HIGH:
if (buttonState == HIGH)
// turn LED on:
digitalWrite(ledPin, HIGH);
else
// turn LED off:
digitalWrite(ledPin, LOW);
// have some delay (optional)
delay(30);
}
[/sourcecode]
Using Potentiometer
================================When you are connecting to different Digital outputs, you will find some doesn’t give you the change of brightness effect, but a switching on/off effect, such as 2. Port 3 is the first PWM output in order, so we will use that.The reason is because we need to have PWM (pulse-width modulation) output to have an analogue-like effect, otherwise we will only have a pure digital output which is only on and off. Read more about PWM here XXX.
[sourcecode language=”cpp”]
/*
Oscar’s project
adjust LED lightness using potential meter
*/
int brightness = 0; // how bright the LED is
int ledPin = 3; // PWM output
void setup() {
// declare pin 9 to be an output:
pinMode(ledPin, OUTPUT);
}
void loop() {
int sensorValue = analogRead(A0);
// sensorValue 0 – 1023
// brightness 0 – 255
brightness = sensorValue/4;
// set the brightness of pin 9:
analogWrite(ledPin, brightness);
// wait for 30 milliseconds to see the dimming effect
delay(30);
}
[/sourcecode]
1 comment
I guess the led symbol is wrongly drawn.