WEEK 6 - EMBEDDED PROGRAMMING

alogirthm for blinking

step 1. start

step 2. initialise the pin

step 3.turn on the led

step4. add a delay

step5. turnoff and go to step 3

// the setup function runs once when you press reset or power the board

void setup() {

// initialize digital pin LED_BUILTIN as an output.

pinMode(0, OUTPUT);

}

  
// the loop function runs over and over again forever

void loop() {

digitalWrite(0, HIGH); // turn the LED on (HIGH is the voltage level)

delay(1000); // wait for a second

digitalWrite(0, LOW); // turn the LED off by making the voltage LOW

delay(100); // wait for a second

}

Copy

you can assign a variable for led pin and change from it.

int ledPin = 0;

// the setup function runs once when you press reset or power the board

void setup() {

  

pinMode(ledPin, OUTPUT);

}

  

// the loop function runs over and over again forever

void loop() {

digitalWrite(ledPin, HIGH); // turn the LED on (HIGH is the voltage level)

delay(1000); // wait for a second

digitalWrite(ledPin, LOW); // turn the LED off by making the voltage LOW

delay(100); // wait for a second

}



select and change values of pin by looking into xiao pinout














Copy

you can use the default code in examples which works fine or can choose to write your own

default example code for digital button in arduino

algorithm fro simple button and switch

step 1. start

step 2. initialise button and led pins

step 3. setup button pin as input and ledpin as output

step 4. if button is pressed, then led should turn on, go to step 6

step 5. turn led off

step 6. go to step 4

const int buttonPin = 27; // the number of the pushbutton pin

const int ledPin = d7; // the number of the LED pin

  


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);

}

}
Copy

the result is simple and direct

Boolean means a result that can only have one of two possible values: true or false.

here we nee d the push button to act as a switch .

algorithm for button and led with boolean flag

step1. start

step2. initialise the pin numbers

step3. setup the led pin as output and button pin input

step4. if the button is pressed set a flag to invert.

step5. turn ledpin to the state of the flag

step5. go to step 4

const int buttonPin = 27; // the number of the pushbutton pin

const int ledPin = D7;

// the number of the LED pin

bool flag = false;

  

// 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)

{

if(flag = !flag); //flag=!flag

  

}

digitalWrite (ledPin, flag);

}
Copy

the result seems like having some issue.

the button is working sometimes and not wrking otherstimes

THIS IS DUE TO THE LIMITATIONS OF THE PHYSICAL BUTTON COMING in BETWEEN . SO, WE NEED TO INTRODUCE A DELAY TO ACCOUNT FOR "BOUNCING". THIS ISSUE IS ADDRESSED IN THE FOLLOWING VIDEO.

so i rewrited this delay(200) code by adding a delay in the loop to introduce "debouncing".

const int buttonPin = 27; // the number of the pushbutton pin

const int ledPin = 1;

// the number of the LED pin

bool flag = false;

  

// 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)

{

delay(200);// delay given to debounce the button.

if(flag = !flag); //flag=!flag

  

}

digitalWrite (ledPin, flag);
Copy

now the issue is resolved.

aNOTHER ISSUE AROSE WHERE THE LED BEGINS BLINKING CONTINUOUSLY WHEN PRESSED.

i introduced one more BOOLEAN check to RESOLVE this issue.

const int buttonPin = 27; // the number of the pushbutton pin

const int ledPin = 1;

// the number of the LED pin

bool flag = false;

bool pressed = false;

  

// 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)

{

if (pressed == false) // introduced thin boolean variable to cater teh blinking effect

{

flag = !flag; //flag=!flag

pressed = true;

}

  
  
  

}

else{

pressed = false;

delay(50);

}

  
  

  
  

digitalWrite (ledPin, flag);

  
  
  
  
  

}
Copy

i think now all the above mentioned issues are resolved.

const int buttonPin = 27; // the number of the pushbutton pin

const int ledPin = 1;

// the number of the LED pin

bool flag = false;

bool pressed = false;

  

// variables will change:

int buttonState = 0; // variable for reading the pushbutton status

  

void setup() {

Serial.begin(9600);//initalise serial on 9600 baud rate

  

// initialize the LED pin as an output:

pinMode(ledPin, OUTPUT);

// initialize the pushbutton pin as an input:

pinMode(buttonPin, INPUT);

  

delay(1000);

Serial.println("led test");

  

}

  

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)

{

if (pressed == false) // introduce this boolean variable to cater teh blinking effect

{

Serial.println(buttonState);

Serial.println("button is pressed");

flag = !flag; //flag=!flag

pressed = true;

}

  
  
  

}

else{

pressed = false;

delay(50);

}

  
  

  
  

digitalWrite (ledPin, flag);

  
  
  
  

}
Copy

lets explore recursive function with the help of llm - chat gpt3.5 turbo for time being..

prompt

write an Arduino sketch that toggles through a series of LEDs when a push button is pressed? The LEDs should be connected to pins 26, 0, and 1, and the push button should be connected to pin 27. Please include code for debouncing the button

prompt
write an Arduino sketch that toggles through a series of LEDs when a push button is pressed? The LEDs should be connected to pins 26, 0, and 1, and the push button should be connected to pin 27. Please include code for debouncing the button
Copy

the promt i used for chat gpt

// constants won't change. They're used here to set pin numbers:

const int buttonPin = 27; // the number of the pushbutton pin

const int ledPins[] = {26, 0, 1}; // array of LED pins

const int numLeds = sizeof(ledPins) / sizeof(ledPins[0]); // number of LEDs

int currentLedIndex = 0;

  

// variables will change:

int buttonState = 0; // variable for reading the pushbutton status

  

void setup() {

Serial.begin(9600); // initialize serial on 9600 baud rate

  

// initialize the LED pins as outputs:

for (int i = 0; i < numLeds; i++) {

pinMode(ledPins[i], OUTPUT);

}

  

// initialize the pushbutton pin as an input:

pinMode(buttonPin, INPUT);

  

delay(1000);

Serial.println("led test");

}

  

void toggleLED(int index) {

// Turn off all LEDs

for (int i = 0; i < numLeds; i++) {

digitalWrite(ledPins[i], LOW);

}

// Turn on the specified LED

digitalWrite(ledPins[index], HIGH);

}

  

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) {

// Toggle to the next LED

currentLedIndex = (currentLedIndex + 1) % numLeds;

// Turn on the LED at the current index

toggleLED(currentLedIndex);

// Wait for button release

while (digitalRead(buttonPin) == HIGH) {

delay(50); // debounce delay

}

}

}
Copy

code chat gpt provided

the result