Homework 3

I tried to change the LED fade speed when pushing the button but I couldn’t figure out how to integrate the code.

 

<pre>

/*
Button

Turns on and off a light emitting diode(LED) connected to digital pin 13,
when pressing a pushbutton attached to pin 2.

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 an LED on the board
attached to pin 13.

created 2005
by DojoDave <http://www.0j0.org&gt;
modified 30 Aug 2011
by Tom Igoe

This example code is in the public domain.

http://www.arduino.cc/en/Tutorial/Button
*/

// constants won’t change. They’re used here to set pin numbers:
const int buttonPin = 2; // the number of the pushbutton pin
//const int ledPin = 9; // the number of the LED pin

// variables will change:
int buttonState = 0; // variable for reading the pushbutton status

int ledpin = 9; // the PWM pin the LED is attached to
int brightness = 0; // how bright the LED is
int fadeAmount = 5; // how many points to fade the LED by

void setup() {
// initialize the LED pin as an output:
pinMode(ledPin, OUTPUT);
// initialize the pushbutton pin as an input:
pinMode(buttonPin, INPUT);
}

// the loop routine runs over and over again forever:
void loop() {
// set the brightness of pin 9:
analogWrite(ledPin, brightness);
// read the state of the pushbutton value:
buttonState = digitalRead(buttonPin);

// change the brightness for next time through the loop:
brightness = brightness + fadeAmount;

// reverse the direction of the fading at the ends of the fade:
if (brightness <= 0 || brightness >= 255) {
fadeAmount = -fadeAmount;
}
// check if the pushbutton is pressed. If it is, the buttonState is LOW:
if (buttonState == LOW) {
// turn LED on:
delay (30);
} else {
// turn LED off:
delay (5);
}
}

}

</pre>