The Arduino platform is a hardware board that offers a hardware-software integrated creative device development platform. The Arduino boards can be interfaced with openly available peripheral devices and custom programs can be written and loaded (embedded) into the Arduino development board:

These programs in turn control and interact with various peripheral components attached with the Arduino board. Thus by using the Arduino development boards; device designers and engineers can quickly create a running prototype of their imaginations. The best part is that the Arduino hardware and software eco-system is open source.

There are many different types of Arduino boards available in the market. Depending upon the processor speed, number of general purpose input/output pins and different power...

Developing and prototyping with the Arduino platform is similar to working on any other embedded system. A general overview of the prototyping process is depicted in the following diagram:

The first step in the prototyping process is to write the embedded program that we will load into the micro-controller board. The term "embedded" is derived from something being hidden. Since the program is loaded into a micro-controller board which cannot be easily seen or deciphered, therefore the program is referred to as an embedded program. Once the program has been written and compiled successfully, it is loaded into the Arduino Uno board.

Once the program is compiled and loaded into the Arduino Uno development board, the next step is to setup the device prototype. A device prototype is the...

In this section we will briefly look at how to setup an Arduino Uno development board and its corresponding Integrated Development Environment (IDE).The process of the first time setup will depend upon the operating system of the computer and is available at the following Arduino Foundation website addresses. It is expected that the reader will perform the setup prior to proceeding further.

As the majority of computer users worldwide use the Windows operating system, this book will provide some practical observations while setting up the Arduino Uno board on...

In this section we will study the general structure of an Arduino sketch. After going through this section you will be able to understand the important parts of an Arduino sketch. This section will also explain how each part of an Arduino sketch gets executed in the Arduino development board.

Arduino C programs are called sketches. A basic sketch structure needs at least two functions in the program body. These functions are listed as follows:

• setup()
• loop()

These functions should always have a same name that is, setup() and loop(). The Arduino development board is pre-programed to execute a loaded sketch by looking for these two function names in the body of a sketch. So if these two function names are not present in the C sketch, then the Arduino IDE will not even compile the sketch successfully. Instead the following errors will be...

Now let us jump into some hands-on activity. In this section we will study an existing Arduino sketch that shipped with the Arduino IDE. The sketch we are going to study is the world famous "blink" program, which is like the Hello World of the embedded programming world. The Arduino IDE installation comes preloaded with a lot of example sketches. All the example sketches are available for use from the File > Examples menu.

Once you attain a minimum level of understanding, you will be able to start exploring more of these examples on your own. Let us inspect and understand the blink program. Fire up the Arduino IDE on your computer and navigate to the File > Examples > 01.Basic > Blink menu. The Blink program will open in a new Arduino IDE window.

The first point to note in the program is the one time configuration that...

The first step in the process is to connect the Arduino Uno development board to the Computer using the USB-A to USB-B cable. The USB-A end of the cable will go into the computer's USB-A port. While the USB-B end of the cable will get plugged into the USB-B port on the Arduino board.

After the Arduino board has been firmly connected to the computer, launch (or re-launch if already open) the Arduino IDE so that the Arduino board get auto detected by the IDE.

Navigate to the menu, Tools | Port, there should be an auto detected port, COM6 (in the picture shown next). If the port is not selected by default, then go ahead and select it manually.

Sometimes it may take a few extra seconds for the board to get auto detected. If the board fails to get detected try to close the IDE and re-launch the IDE again...

In this section we will quickly look at the commonly used in-built function in the Arduino C sketches. These functions will help us in performing basic tasks while interfacing with various devices. Unless you are attempting advanced sketches, the following functions will be very helpful in building most of the Arduino sketches. Apart from the below in-built functions, device specific header files and functions are also used - we will understand this aspect in the chapter for Day 2 while understanding how to use a header library for a sensor.

In this section, let us look at the commonly used in-built C functions that are used for digital I/O. The following two functions are used for sending a digital signal out via a digital pin. First the digital pin has to be configured in output mode (for sending) in the setup() function:

pinMode(PIN-NUMBER, I/O-MODE) 

Let us say we want to send a digital signal via digital Pin 7, then the following line of code will be used:

pinMode(7, OUTPUT) 

This is how we configure the digital pin in output mode so that it can send digital signals. The next step is to understand how to actually send a digital signal. For sending a digital HIGH signal the following line of code must be used:

digitalWrite(7, HIGH) 

Similarly, for sending a digital LOW signal the following line of code must be used:

digitalWrite(7, LOW) 

Note that some peripheral components might need...

In this section, let us take a look at the commonly used in-built C functions that are used for analog I/O. To begin with we will learn how analog input is measured by the Arduino sketch. An Arduino sketch uses the following function to obtain an analog reading from its analog pins:

analogRead(<pin-number>) 

For example, if we want to read the analog signal value from analog pin A5, we must use the following function call:

int value;                // declare integer variable 
value = analogRead(A5);   // read analog value 

The above function will return an integer value between 0 and 1023, depending upon the voltage value on the pin. The number 0 to 1023 will be proportional to the voltage range of the Arduino Uno board i.e. 0 to 5 volts.

Next we will look at techniques to write analog signals on both analog as well as digital pins. Digital pins...

Now that we have reached the end of this chapter, let us try to perform some interesting self-learning exercises. These exercises have been devised to simulate your thoughts and enable to utilize what you have learnt so far.

• Increase the delay between the blinking of the on-board LED to 2 seconds by using the statement delay(2000) in the loop() function.
• Decrease the delay between the blinking of the LED to 0.5 seconds. Remember 1 second = 1000 milliseconds.
• Wrap the LED blinking portion of the code in a for loop, to run 10 times.

A list of important concepts that you should remember has been provided so that you can easily recall the main points learnt in this chapter.

• In the Arduino parlance, a "program" is called a "sketch".
• Only one sketch can be loaded at a time into the Arduino board.
• The setup() function runs only once every time the board is either reset or powered up.
• The loop() function keeps running infinitely.
• Peripheral devices are connected using the digital and analog I/O pins.
• Peripheral devices may be powered by using the 5 volt and 3.3 volt power supply pins.
• The Arduino Uno board has 32 KB of memory. It must be used efficiently for managing complex scenarios.
• Arduino power supply pins should NOT be used for high powered devices such as motors.
• As the number of peripheral devices increase, the Arduino board's power supply pins may not be able...

In this chapter we concentrated on understanding the basics of writing a sketch; loading and executing the sketch in the Arduino board. We also learnt the most commonly used in-built C functions, followed by a detailed understanding to sending and receiving digital and analog signals. So far our journey was focused on the basics and the sketch that we studied was contained within the Arduino Uno board.

In the next chapter we are going to get introduced to building breadboard circuits with external hardware components and then learn how to interface them with the Arduino board. We will also take an in-depth look at various common electronic components used for Arduino prototyping. It is important to grasp the basic concepts as these will go a long way and make you fully self-reliant in your future endeavors.