Arduino 101

Arduino 101 for beginners

Introduction to Arduino

Arduino is an open-source microcontroller and software IDE ( Integrated Development Environment) that is literally changing the world.

Why Arduino?
Arduino is:
•Open-source software – Arduino IDE (free)
•Inexpensive and Open-source hardware – If you have circuit design experience, you can clone and manufacture your own Arduino board.
•Easy-to-use for beginners
•Easy to write and debug the code
•It works with Mac and Windows

Arduino Hardware
Arduino boards are easy to use and ready to power your first creative projects.
* Note: It is recommended to use the authentic Arduino board instead of the counterfeit boards that says, ‘Arduino compatible’. By buying the original Arduino we can help the open-source community.
Entry level Arduino boards
The following boards are the best to start learning the basics of electronics and coding. For enhanced features and Internet of things capable boards, refer to Ardunio website.

Arduino - UNO
The Arduino UNO is the best board to get started with electronics and coding. If this is your first experience tinkering with the platform, the UNO is the most robust board you can start playing with. The UNO is the most used and documented board of the whole Arduino family.

Microcontroller	Atmega 328P
Operating Voltage	5V
Input Voltage (recommended)	7-12V
Input Voltage (limit)	6-20V
Digital I/O Pins	14 (6 PWM output)
PWM Digital I/O Pins	6
Analog Input Pins	6
DC Current per I/O Pin	20 mA
DC Current for 3.3V Pin	50 mA
Flash Memory	32 KB (ATmega328P)
SRAM	2 KB (ATmega328P)
EEPROM	1 KB (ATmega328P)
Clock Speed	16 MHz
LED_BUILTIN	Pin 13

Arduino – UNO - Pinouts
The Arduino UNO pinout diagram given here is an entry level introduction only. Expert level users can refer to the Arduino website for detail information..

UNO pins - Specialized functions
Serial: 0 (RX) and 1 (TX). Used to receive (RX) and transmit (TX) TTL serial data.
PWM: 3, 5, 6, 9, 10, and 11. Provide 8-bit PWM output with the analogWrite() function
LED: 13. There is a built-in LED driven by digital pin 13. When the pin is HIGH value, the LED is ON, when the pin is LOW, it’s OFF.
AREF. Reference voltage for the analog inputs. Used with analogReference() function.
Reset. Used to reset the microcontroller. Typically used to add a reset button to shields which block the one on the board

Arduino – UNO - Power
The Arduino Uno board can be powered via the USB connection or with an external power supply through the DC power jack. The power source is selected automatically.

UNO – Power Pins
1) Vin: You can supply voltage through this pin, or, if supplying voltage via the power jack, access it through this pin.
2) 3V3. A 3.3 volt supply generated by the on-board regulator. Maximum current draw is 50 mA.
3) 5V: This pin outputs a regulated 5V from the regulator on the board. You can power other devices from the 3.3V or 5V pins.
Note: do not supplying voltage to the board via the 5V or 3.3V pins, it can damage your board. These pins are output, not input.
4) GND. Ground pins provide a current return to your circuit.
5) IOREF. This pin provides the voltage reference to your shield with which the microcontroller operates.

Arduino UNO - Software

The open-source Arduino Software (IDE) makes it easy to write code and upload it to the board. It runs on Windows, Mac OS, and Linux. The environment is written in Java and based on Processing and other open-source software. In order to program the Arduino microcontroller, you need to install the Arduino Desktop IDE ( Integrated Development Environment). The Arduino Software (IDE) allows you to write programs and upload them to your board.
- Install the Arduino IDE from Arduino Software Page. https://www.arduino.cc/en/Main/Software
-Scroll down to “Download the Arduino IDE “
-Select the installer according to your computer operating system. Foe example, select “Windows Installer” for Windows7 and up.
-Follow the on-screen wizard and finish the installation.

Arduino Software (IDE)
The Arduino IDE - Integrated Development Environment - contains a text editor for writing code, a message area, a text console, a toolbar with buttons for common functions and a series of menus.

Writing Sketches
Programs written using Arduino IDE are called sketches. These sketches are written in the text editor and are saved with the file extension .ino. The message area gives feedback while saving and exporting and also displays errors. The console displays text output by the Arduino IDE, including complete error messages and other information. The bottom righthand corner of the window displays the configured board and serial port. The toolbar buttons allow you to verify and upload programs, create, open, and save sketches, and open the serial monitor.

Arduino IDE

Arduino IDE - Toolbar

Verify
Checks your sketch for errors compiling it. Note: Ardunio code is also called “Sketch”.

Upload
Compiles your code and uploads it to the code to your board configured board.

New
Creates a new sketch.

Open
Clicking it will open a Sketchbook it within the current window overwriting its content.
If you want to open a file in a folder then use the File | open menu instead.

Save
Saves your sketch.

Serial Monitor
Opens the serial monitor that displays a serial message sent from the Arduino board over USB or serial connector

Arduino – IDE - Sketch
The Arduino Software (IDE) uses the concept of a sketchbook: a standard place to store your programs (or sketches). The sketches in your sketchbook can be opened from the File > Sketchbook menu or from the Open button on the toolbar.The first time you run the Arduino software, it will automatically create a directory for your sketchbook. You can view or change the location of the sketchbook location from with the Preferences dialog.
Now, you have the basics of Arduino hardware and software and we are done with the introduction. We are ready to start the hands-on projects

Remember, our number one focus is safety and our number one goal is to have fun.

Project 1a. On-board LED Blink

This project requires only Arduino board and a USB-B cable.
We will use Arduino UNO and the on-board LED lamp connected to pin 13 of the UNO.
-Start the Arduino IDE
-Open the “LED blink” example sketch: File -> Examples -> 01.Basics -> Blink

Upload the Blink sketch to your Arduino
- Connect the UNO to your computer USB port
- Select your Arduino type. Tools -> Board -> Arduino/Genino UNO
- Select the Serial Port. Tools -> Port -> COMx(Ardunio/Genino UNO
COMx can be COM3, COM6, COM10 or any COM that is available for your Arduino
- Upload the sketch.
Wait few seconds after the upload, you should see the on-board LED starts to blink (orange).

If it does, congratulations! You have successfully configured your Arduino hardware and software.

Project 1b. LED Blink

This project requires Arduino board, LED diode, 200 ohm or equivalent resistor, breadboard (optional), and a USB-B cable.

-Note: the LED’s short leg is cathode (-) and it should be connected to GND (ground). The long leg is anode (+) and it will be connected to a digital pin through a resistor.

-Unplug the power cable from the board until you finish the circuit connection.
-Connect the circuit as shown in the figure.
-Connect the short leg of the LED to in GND of the UNO
- Connect the long leg of the LED to a resistor and connect the resistor to pin 13 of the UNO.
-Connect the board to your computer USB port.
-If you have done project 1a, then the same code uploaded to the UNO will work for project 1b as well.
- If you have not done project 1a, upload the LED blink code to your Arduino board by referring to the project 1a, section “Upload the Blink sketch to your Arduino”.

Note: if you don’t have a resistor, you connect the LED directly to the UNO pins.

If the LED starts to blink, You have successfully done 1b

Arduino LED Blink Circuit

Project 2. RGB LED

This project requires Arduino board, RGB LED (common cathode), 200 ohm or equivalent resistors, breadboard, and a USB-B cable.

RGB LED
You can use the RGB(Red-Green-Blue) lights to add more functionalities to your project. You can also obtain additional colors like Magenta, Cyan, Yellow, and White by combining the basic RGB colors. The basic RGB led is available in two configurations, common anode and common cathode. In this tutorial, we will use the common cathode RGB.
-In a common cathode configuration, the longest leg is cathode and it will be connected to ground.
-Red, green, and blue legs of the RGB LED will be connected to PWM pins. In our example, we will use pin 11, 10, and 9 of the Arduino UNO.

Circuit connection
-Unplug the power cable from the board until you finish the circuit connection.
-Connect the circuit as shown in the figure.
- Connect the longest leg of the RGB to in GND of the UNO
- Connect the Red to pin 11, blue to pin 10, and green to pin 9 of the UNO. Use 200-ohm resistors for the red, blue, and green pins of the RGB.

For project 2, we will write our own code.
Note: If you don’t use resistors, please be nice to your eyes.
- Avoid looking directly into the RGB
- Reduce the PWM to a value below 150 inside the code in lieu of 255 (given in the code)

Arduino RGB LED Circuit

Write your first Arduino code

- Start the Arduino IDE
- File -> new
This will open a template sketch
- File -> Save as
By default, Arduino saves sketches to the
Arduino folder. You can create your own folder.
Note: the folder name must be the same as the file name.
- Inside the new sketch, before the “void setup” add the following pin initialization code:
//RGB LED pins (~PWM)
   int green = 9;    //LED red
   int blue = 10;    //LED green
   int red = 11;     //LED blue
-The code that starts with “//” is a comment line. It is not part of the code.
-under the “void setup”, add the setup code lines inside the curly brackets. { … }
-Under the “void loop”, add the main code that will turn the RED, GREEN, and BLUE lights with two second delay.

- Verify and upload the code to your Arduino board.
- Observe the LED changing colors.
- Red -> Blue -> Green -> White two seconds delay between each colors.

-Have fun by changing the PWM values from 0 to 255 to change the brightness of the LED and try to combine the basic RGB colors to get a new color.
-What do you get if you combine RED and GREEN?
Hint: (red, 255), (green, 255), (blue, 0)

/* RGB LED TEST
  By. Fekadu Debebe
  April 21/2019
*/
//RGB LED pins (~PWM)
int green = 9;    //LED red
int blue = 10;    //LED green
int red = 11;     //LED blue

// Setup instructions
void setup()
{
  Serial.begin(9600); // serial monitor
  // Arduino pins input or output
  pinMode(red, OUTPUT);
  pinMode(green, OUTPUT);
  pinMode(blue, OUTPUT);
}
// Main loop
void loop()
{
  // PWM value from 0 to 255 
  //Red, bright
  analogWrite(red, 255);  // 100% PWM
  analogWrite(green, 0);  // Green OFF
  analogWrite(blue, 0);   // Blue OFF
  delay(2000);            // wait for 2 sec
  // blue, bright
  analogWrite(red, 0);
  analogWrite(green, 0);
  analogWrite(blue, 255);
  delay(2000);
  //Green, bright
  analogWrite(red, 0);
  analogWrite(green, 255);
  analogWrite(blue, 0);
  delay(2000);
  // white, bright
  analogWrite(red, 255);
  analogWrite(green, 255);
  analogWrite(blue, 255);
  delay(2000);
 }

Arduino RGB Circuit simulation (TinkerCAD)

If you have enjoyed the Arduino beginner tutorial, then check out the intermediate and advanced Arduino projects under "DIY - Robotics" section of this website.

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