A virtual machine (VM) is a virtual environment which functions as a virtual computer system with its own CPU, memory, network interface, and storage, created on a physical hardware system.VMs are isolated from the rest of the system, and multiple VMs can exist on a single piece of hardware, like a server. That means, it as a simulated image of application software and operating system which is executed on a host computer or a server.It has its own operating system and software that will facilitate the resources to virtual computers.Characteristics of virtual machinesThe characteristics of the virtual machines are as ... Read More

The equivalent of deep sleep in Arduino would be the Power Down mode, which consumes the least power out of all the sleep modes. While this has already been covered in another article, but for the sake of completeness, here’s a brief on the sleep modes in Arduino.Arduino’s microcontroller, ATmega328P has 6 sleep modes, of which 5 are available with the avr/sleep.h library.Idle modeADC Noise ReductionPower-downPower-saveStandbyExtended StandbyEach mode has different wake-up modes and different power consumption.The Idle mode is easiest to wake up from and the Standby and Power down mode is the most difficult to wake up from (you ... Read More

In this article, we will, as the title suggests, make the Arduino sleep, and wake it up using an interrupt. Arduino’s microcontroller, ATmega328P has 6 sleep modes, of which 5 are available with the avr/sleep.h library. Each mode has different wake-up modes and different power consumption.Arduino’s microcontroller, ATmega328P has 6 sleep modes, of which 5 are available with the avr/sleep.h library.Idle modeADC Noise ReductionPower-downPower-saveStandbyExtended StandbyEach mode has different wake-up modes and different power consumption.The Idle mode is easiest to wake up from and the Standby and Power down mode is the most difficult to wake up from (you can only ... Read More

The Time library provides you with timekeeping functionality on the Arduino. The latest version of the library is documented here.To install it, search for Time in the Library Manager and install the library by Michael Margolis.You’ll have to scroll a bit to find this library.Once the library is installed, if you go to File → Examples → Time, you will be able to see several examples of integrating this library with various sources: GPS, NTP, RTC, etc.The basic idea is that you can set time using the functions −setTime(hours, minutes, seconds, days, months, years);OR, setTime(t);where t is the special time_t ... Read More

An RTC module keeps track of time once an initial time input is provided to it. This input can come from several sources (NTP, GPS, etc.). The RTC module usually comes with its own crystal oscillator, and even its own battery, so that the timekeeping continues, even if there is a power disturbance on the Arduino.Circuit Diagram −We will use the DS3231 module. It uses I2C for communication (SDA and SCL lines). The circuit diagram is shown below −As you can see, the Vcc pin of DS3231 is connected to 5V, GND to GND, SDA to A4 (SDA) and SCL ... Read More

Follow the steps given below to browse Arduino libraries by category on Arduino website −Go to http://arduino.cc/Click Documentation → ReferenceClick Libraries from the left menu.The libraries can now be found in the categorized form on this pageClick the category of your interest and explore the available libraries.

goto is a control structure in Arduino, like in C, and it is used to transfer the program flow to another point in the program. It is highly discouraged, as many programmers agree that you can write every algorithm you want without the use of goto.Excessive use of goto makes it very difficult to debug programs, or, in some cases, creates program flows which are impossible to debug. It is assumed that you will read further only if you absolutely have to use goto.SyntaxThe syntax for using goto is −goto label; label:    //statementsExampleThe following example demonstrates this −void ... Read More

The reference (&) and dereference operators (*) in Arduino are similar to C. Referencing and dereferencing are used with pointers.If x is a variable, then its address is represented by &x.Similarly, if p is a pointer, then the value contained in the address pointed to by p is represented by &p.Examplevoid setup() {    // put your setup code here, to run once:    Serial.begin(9600);    Serial.println();    int x = 10;    int *p;    p = &x; //p now contains the address of x    Serial.print("The value stored in the address pointed by p is: ");Serial.println(*p); } ... Read More

Compound operators in Arduino work just like in C, and they help save you some writing time, and also reduce the number of lines in your code. As the name seems to suggest, compound operators combine multiple operators.The following table lists the compound operators in Arduino.Assume that a and b are integers having values a = 5 and b = 2 in all the following examples −OperatorDescriptionExampleOutput++Incrementa++a=6--Decrementa--a=4+=Compound Additiona+=ba=7-=Compound subtractiona-=ba=3*=Compound multiplicationa*=ba=10/=Compound divisiona/=ba=2%=Compound remaindera%=ba=1&=Compound bitwise ANDa&=ba=0|=Compound bitwise ORa|=ba=7^=Compound bitwise XORa^=ba=7

In order to convert variables from one type to another, you use the CAST operator. The syntax is −(type) var;Where var is the variable to be casted, and type is the new type to which you wish to convert it. For example, if you have a variable of type float, and wish to cast it as an int.ExampleHere’s how you can do it −float f; int i; void setup() {    // put your setup code here, to run once:    f = 5.6;    i = (int) f;    Serial.println(f);    Serial.println(i); } void loop() {   ... Read More