Arduino BLINK Blueprints: Get the most out of your Arduino to develop exciting and creative LED-based projects

Beginners often get confused when they discover Arduino projects. When looking for Arduino, they hear and read such terms as Uno, Zero, and Lilypad. The thing is, there is no such thing as "Arduino". In 2006, the Arduino team designed and developed a microcontroller board and released it under an open source license. Over the years, the team has improved upon the design and released several versions of the boards. These versions mostly had Italian names. There are numbers of boards that the team has designed over the past 10 years:

The Arduino team didn't just improve on design, they invented new designs for specific use cases in mind. For example, they developed Arduino Lilypad to embed a board into textiles. It can be used to build interactive T-shirts. The following table shows the capability of different Arduino boards. Arduino boards may differ in their appearance, but they have a lot in common. You can use the same tools and libraries to program:

As Arduino boards' design and schematics are open source, anyone can use and change the original board design and can create their own version of an Arduino-compatible board. Because of that, you can find countless Arduino clones on the web which can be programmed using the same tools and libraries used for original Arduino boards.

With so many options available, it becomes challenging for a person to decide which Arduino board to use for a project. The Arduino family is huge, and it is impossible to read about each and every board and decide upon which board to use for a particular project.

The following flowchart simplifies the process by providing a decision tree for widely-used Arduino boards and the most common use cases/applications:

If you are not sure what you will build and what hardware capabilities are required, start building your prototype using Arduino UNO. Arduino UNO has the best documentation and best support. It is also the most compatible of all Arduino boards. Most of the existing libraries and shields are compatible with Arduino UNO. And finally, most of the code that has been written on earlier versions of Arduino boards will also work with Arduino UNO.

Throughout this book, we will use the Arduino UNO board.

"UNO" means one in Italian, and it was chosen to mark the release of Arduino IDE v1.0. It is the first in a series of USB Arduino boards. As mentioned before, it is one of the most widely used boards in the Arduino Family:

In this section you will get introduced to different components of the Arduino UNO board.

Arduino IDE is supported on all major operating systems, initially Windows, Mac, and Linux.

If you have used IDEs such as Visual Studio, XCode, and Eclipse before, you'd better lower your expectations, because Arduino IDE is very simple. It mainly consists of an editor, a compiler, a loader, and a serial monitor. It has no advanced features such as a debugger or code completion:

Let's look into each button separately:

As mentioned in the Arduino UNO section, there are two ways you can power up your Arduino UNO. One is by using a USB cable connected to your computer and the second one is by a 12 V external power supply. Please make sure that you don't use a power supply greater than 20 volts as you will overpower and thereby destroy your Arduino Board. The recommended voltage for most Arduino models is between 6 and 12 volts.

This is the last step before you write your "Hello World" program with your Arduino:

In this example, the Arduino board will communicate with the computer using the serial port, which can be viewed on your machine using the Serial Monitor.

Write the following code to your Arduino editor:

void setup()                    // run once, when the sketch starts
{
  Serial.begin(9600);           // set up Serial library at 9600 bps
  
  Serial.println("Hello world!");  // prints hello with ending line break 
}

void loop()                       // run over and over again
{
                                  // do nothing!
}

Serial.begin sets up Arduino with the transfer rate we want, in this case 9600 bits per second. Serial.println sends data from Arduino to the computer.

Once you compile and upload it to your connected Arduino board, open Serial Monitor from the Arduino IDE. You should be able to see the Hello world! text being sent from the Arduino board:

In the previous example, serial library was used to send a command from Arduino to your computer. In this example, you will send a command from the computer, and Arduino will do a certain operation (turn on/off LED) based on the command received:

int inByte; // Stores incoming command

void setup() {
Serial.begin(9600);
pinMode(13, OUTPUT); // LED pin
Serial.println("Ready"); // Ready to receive commands
}
void loop() {
  if(Serial.available() > 0) { // A byte is ready to receive
    inByte = Serial.read();
    if(inByte == 'o') { // byte is 'o'
      digitalWrite(13, HIGH);
      Serial.println("LED is ON");
      }
      else 
      { 
        // byte isn't 'o'
        digitalWrite(13, LOW);
        Serial.println("LED is OFF");
      }
   }
}

The inByte function will store the incoming serial byte. From the previous example, you should be familiar with the commands written in the setup function. In the loop function, first you need to know when a byte is available to be read. The Serial.available() function returns the number of bytes that are available to be read. If it is greater than 0, Serial.read() will read the byte and store it in an inByte variable. Let's say you want to turn on the LED when the letter 'o' is available. For that you will be using the if condition, and you will check whether the received byte is 'o' or not. If it is 'o', turn on the LED by setting pin 13 to HIGH. Arduino will also send an LED is ON message to the computer, which can be viewed in Serial Monitor:

If it is any other character, then turn off the LED by setting pin 13 to LOW. Arduino will also send an LED is OFF message to the computer, which can be viewed in Serial Monitor: