Week 7 - Journal

Task description as mentioned on the portal: design and program a smart device that performs a certain function or solves a problem: program Arduino UNO to read signals from multiple input components (Sensor, Switch, or variable resistor) to control multiple action components (Motor, Buzzer, LED...etc) using Arduino C (Text Code). 

Ideation: I would like to build a smart alarm that looks like a mini figure with a hat and two LEDs that mimic his eyes. 

In his hat, there is a light sensor that sends a signal to the LEDs when he wears the hat at night so they glow with calming light during sleep time. When he takes the hat off in the morning, the LEDs will go to a low mode and a servo motor will move his hands 45 degrees to great the user and wish him/her a good day!  

Unlike last week when we used the code blocks, this week we will learn how to write the code from scratch on Arduino IDE. When we open a new sketch from the file menu,  two commands will be written already on the program interface:

void setup() {

 // put your setup code here, to run once:

}

void loop() {

 // put your main code here, to run repeatedly:

}

• Between the curly bracket, this is where we write our code. And what is written between the double slashes is a general comment that does not have any format just to remind myself of any note or description I want to associate with the code below. 

• The shortcut for auto-format (Ctrl+t) is used for a better alignment of the code and to spot errors easily.

• "void setup" section is for identifying the pins and labeling them as an output or an input as this function needs to be communicated once to the program.

• "void loop" will include commands that are more likely to be repetitive functions. 

Understanding  Arduino syntax: 

• Arduino is case sensitive and small letters have to remain small, and capital letters have to remain capital. 

• How we store data on Arduino depends on the type of data:

int x = analogRead(9); //to store interval/real number//

long y = analogWrite(A0); //extended size variables for number storage//

float z = y/10 //to store decimal digits//

char letter = "e"; //to store letters//

• Components are defined based on two parameters: their pin number and if they are considered to be an input/output. 

• When we associate the LED color with the pin number, our code will be more readable, and if I need to change wiring we just need to change the PIN number, not all code:

 Int red = 8;

• Serial Monitor is a communication method to transfer data between devices which in this case the laptop and Arduino and the USB (universal serial bus) is the link between them. We use this feature to display output and track values, and also to create wireless communication between devices using the Bluetooth module. What should be added to the void setup code is to notify Arduino to activate this feature:  

Serial.begin(9600); 

and to void loop some of these functions.

Serial.print("Temp = "); 

or/and 

Serial.println();

• It took me a while to understand to write variables to control an RGB LED using a potentiometer that uses an analog pin with range of different value numbers: 

void loop() {

int sensor_reading = analogRead(A0);

int interval = map(analogRead(A0), 0, 1023, 100, 2000);

What does it mean by looping? 

• Looping is about repeating functions endlessly or until another condition interrupts this loop. 

• Using the main loop "void loop"  to run one function like LED fading is not ideal in case of the need of adding more functions. 

Example for such a code: from file -> example -> basics -> Fading: 

void loop() {

analogWrite(led, brightness);

brightness = brightness + fadeAmount;

if (brightness <= 0 || brightness >= 255) {

   fadeAmount = -fadeAmount;

   } 

   delay(30);

   }

• Creating a loop function using For Loop will give room for another function to be added and remain repetitive as well outside of the For loop but in the main loop. 

Example for such a code: from file -> example -> analog -> Fading: 

void loop() {

for (int fadeValue = 0; fadeValue <= 255; fadeValue += 5) {

   analogWrite(ledPin, fadeValue);

   delay(30);

 }

• When adding conditions related to the distance between the Ultrasonic sensor and an object, and based on these conditions the LED should blink or fade, the Arduino scan conditions according to their orders in the code and by adding "else" at the end; I am communicating to the Arduino if you could not find non of the above, run this condition and in the cause of this code, the LED bulb will remain glow. 

• In the void loop section, I added the if condition which states when the sensor is uncovered/on, the servo motor will move and rotates the arm as if the robot is waving hands saying "good morning" to the user, and LEDs will be turned off. 

• And if the sensor is covered/off, the LEDs will glow to give the user calming environment at night time, and the motor will remain still. 

void loop() {

 if (digitalRead(onbutton) == HIGH) {

   if (analogRead(Sensor)>800) {

     digitalWrite(LED1, HIGH);

     digitalWrite(LED2, HIGH);

     A.write(POS);

   } else {

     digitalWrite(LED1, LOW);

     digitalWrite(LED2, LOW);

     A.write(180);

     delay(500);

     A.write(0);

     delay(500);

     A.write(180);

     delay(500);

     A.write(0);

   }

• I think I have to consider where I will put the wires, and how I will mount other components like the boards and motor. 

• I have to admit that this week's model needed some adjustments and more planning for a better fit of the components. 

There are different types of mistakes and one of them happens due to lack of sleep. 

To make a long story short, I had to cut the model twice.