# Skills Dev 1 - wting

Created: November 16th, 2020

0

## Exercise 1

Modify the program to Blink on and off every 3 seconds.

0
``````//exercise 1: blink on and off every 3 secs

int ledPin = D2;

void setup() {

pinMode (ledPin, OUTPUT);

}

void loop(){

digitalWrite(ledPin, HIGH);
delay(3000);

digitalWrite(ledPin, LOW);
delay(3000);

}``````
Click to Expand
0
0

## Exercise 2

blink on and off 5 times then stop for 3 sec

0
``````//exercise 2: blink on and off 5 times then stop for 3 sec

int ledPin = D2;

void setup() {

pinMode (ledPin, OUTPUT);

}

void loop(){
for (int i = 0; i < 5; i++){ //repeat 0.5sec blinking for 5 times

digitalWrite(ledPin, HIGH);
delay(500);

digitalWrite(ledPin, LOW);
delay(500);
}

digitalWrite(ledPin, LOW); //stop for 3 sec
delay(3000);

}``````
Click to Expand
0
0

## Exercise 3

0
``````//exercise 3: add a second LED to the circuit and alternate blinks

int led1 = D2;
int led2 = D3;

void setup() {

pinMode (led1, OUTPUT);
pinMode (led2, OUTPUT);
digitalWrite(led1, LOW);
digitalWrite(led2, LOW);

}

void loop(){

digitalWrite(led1, HIGH); //turn on LED 1
delay(500);

digitalWrite(led1, LOW); //turn off LED 1
delay(500);

digitalWrite(led2, HIGH); //turn on LED 2
delay(500);

digitalWrite (led2, LOW); //turn off LED 2
delay (500);

//repeat
}``````
Click to Expand
0
0

## Exercise 1

Modify the cloud function to blink the LED 3 times after it is called

0
``````//connected LED: exercise 1, blink LED 3 times after it is called

int led1 = D2;

void setup() {

//Register Particle function here
Particle.function("led", ledControl);

pinMode (led1, OUTPUT);
digitalWrite(led1, LOW); //LED 1 initial state to be off

}

void loop(){

//nothing to do here

}

int ledControl(String command)
{
int state = LOW;

//find out the state of the led
if(command == "HIGH") {
for (int i = 0; i < 3 ; i++){
digitalWrite(led1, HIGH);
delay(500);
digitalWrite(led1, LOW);
delay(500);
}
}else if (command == "LOW"){
state = LOW;
}else{
return -1;
}

//write to the appropriate pin
digitalWrite(led1, state);
return 1;

}``````
Click to Expand
0
0

## Exercise 2

Instead of passing a `HIGH` Or `LOW` string pass the number of times you would like it to blink.
Set the function to blink that number of times
Finally once it has completed all of the blinking it should turn the LED off .

0
``````//connected LED: exercise 2, set the function to blink that number of times

int led1 = D2;
int value = 0;

void setup() {

//Register Particle function here
Particle.function("led", ledControl);

pinMode (led1, OUTPUT);
digitalWrite(led1, LOW); //LED 1 initial state to be off

}

void loop(){

//nothing to do here

}

int ledControl(String command)
{
int state = LOW;
value = command.toInt();

if(value>0){
for (int i = 0; i < value ; i++){
digitalWrite(led1, HIGH);
delay(500);
digitalWrite(led1, LOW);
delay(500);
}

}
else{
return -1;
}

//write to the appropriate pin
digitalWrite(led1, state);
return 1;

}``````
Click to Expand
0
0

## Exercise 3

Go back to the original program. Now add a second LED to the circuit.
Change the program and cloud function to allow you to control both LEDs remotely

0
``````//connectedled:exercise 3: add a second LED to the circuit, control both LEDs remotely
int led1 = D2;
int led2 = D3;
int value = 0;

void setup() {

//Register Particle function here
Particle.function("led", ledControl);

pinMode (led1, OUTPUT);
digitalWrite(led1, LOW); //LED 1 initial state to be off

pinMode (led2, OUTPUT);
digitalWrite(led2, LOW); //LED 2 initial state to be off

}

void loop(){

//nothing to do here

}

int ledControl (String command)

{
int state = LOW;

//find out the state of the led
if (command == "1") {
digitalWrite(led1, HIGH);
}
if (command == "2"){
digitalWrite(led2, HIGH);
}
if (command == "0"){
state = LOW;

}
if (command == "-1"){
digitalWrite(led1, LOW);
}
if (command == "-2"){
digitalWrite(led2, LOW);

}else{
return -1;
}

//write to the appropriate pin
digitalWrite(led1, state);
digitalWrite(led2, state);

return 1;

}``````
Click to Expand
0
0

## Process & Reflection

For the "making an LED blink" part of the exercise, I think it is quite straightforward by following the instructions. It took a bit of experiments and thinking through what should be changed in coding in the different exercises, as well as the circuit, but it helped me understand the coding and circuits better.

"Making a Connected LED" took longer for me to figure out the coding. I had trouble with exercise 3 in connected LED particularly. I tried several ways in the coding to set up 2 functions on console; however, I wasn't able to control one LED through one function; whenever I try to control one LED through console, both LED will light up. In the end, it only worked when I use one function, and set up different "numbers" corresponding to different actions for particular LED, ex. type in 1 to turn on LED 1; type in 2 to turn on LED 2". I think there should be a better way of controlling the different LED remotely; with more experiments and knowledge in coding, I will probably be more familiar with it.