Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
In order to check if two strings are equal, the .equals() function can be used. This returns a Boolean. True if both the strings are equal, else false. An example code is given below −Examplevoid setup() { // put your setup code here, to run once: Serial.begin(9600); Serial.println(); String s1 = "Hello"; String s2 = "Hello"; String s3 = "World"; if(s1.equals(s2)){ Serial.print("s1 equals s2"); } if(s1.equals(s3)){ Serial.print("s1 equals s3"); } if(s2.equals(s3)){ Serial.print("s2 equals s3"); } ... Read More
The startsWith() function in Arduino helps you determine if a string starts with a specific set of characters. It returns true if the string starts with the substring you specified, else it returns false. An example implementation is given below −Examplevoid setup() { // put your setup code here, to run once: Serial.begin(9600); String String1 = "AB_Test"; String String2 = "CD_Test"; String substr1 = "AB"; String substr2 = "AB*"; if(String1.startsWith(substr1)){ Serial.print("String1 starts with substr1"); } if(String2.startsWith(substr1)){ Serial.print("String2 starts with substr1"); ... Read More
In order to check if a specific substring exists within a string in Arduino, the indexOf() function can be used. This returns the index of the first occurrence of the character or a string that you are searching for within another string. In case the character or string does not exist within the given string, the function returns -1.Example implementations are given in the code below −Examplevoid setup() { Serial.begin(9600); Serial.println(); String s1 = "Hello World"; Serial.println(s1.indexOf('e')); Serial.println(s1.indexOf("Wor")); Serial.println(s1.indexOf('z')); Serial.println(s1.indexOf("Wer")); } void loop() { // put your main code here, to run ... Read More
In order to blink an LED using Arduino, we first connect perform the hardware connections. Choose a pin of your board that supports digital output. We are using the Arduino Uno board, and we will choose pin 7. The circuit will look like this −As you can see, one end of a resistor is connected to pin 7 of Arduino Uno. The other end the resistor is connected to the longer leg (positive) of the LED. The shorter leg of the LED is connected to GND.The value of the resistor can be of the order of 100 Ohms. We'll choose ... Read More
By default, the analogRead in Arduino follows a 10-bit resolution (this may be different for different boards). However, sometimes, you may not need such a high resolution. Often, people wish to set the resolution to 8-bits, to save on storage. This is because an 8-bit value will take just one byte of storage, whereas anything above that will take two bytes of storage.Luckily, Arduino has an inbuilt function to change the resolution of the analog to digital conversion. The function is analogReadResolution() and it takes in the argument as the resolution in bits.So, if you wish to set an 8-bit ... Read More
Converting analog values to digital is a common requirement from microcontrollers in general, and Arduino is no different. Arduino IDE has a built-in analogRead function to facilitate the conversion of analog values to digital.From the programming perspective, the only thing you require to know is the pins of your microcontroller that support ADC. On the Arduino UNO board, the pins A0 to A5 support ADC.Now, let us assume that you've connected your A0 pin to an analog wire (maybe the junction between an LDR and a resistor, or the central leg of a potentiometer).The basic Arduino code to print the ... Read More
In order to access any pin of your board in Arduino, you can simply reference the number of the pin as an integer. On the Arduino boards like Uno, the label is provided for all the I/O pins, and the same label can be used in the code.Thus, both the below expressions are valid −int pin1 = A0; int pin2 = 7;Once the pin number has been defined, depending on your use case, you may need to set the pin as either an input pin or an output pin. This is generally done in the setup (because it is a ... Read More
The general way of using third-party libraries in Arduino is to install them from Tools -> Manage Libraries. We already have a separate post to cover that. However, what if a library you are using for cannot be found in Tools -> Manage Libraries? After all, Manage Libraries only includes those libraries which are present in Arduino Library Manager −http://downloads.arduino.cc/libraries/library_index.jsonSo, how do we use a library not present in Arduino Library Manager? Let's use an example to understand.Consider the TinyGPSPlus library (https://github.com/mikalhart/TinyGPSPlus) which is not available in Arduino's Manage Libraries portal as on 17th March 2021.In order to use this ... Read More
What are interrupts?As the name suggests, interrupts are routines that interrupt the normal code flow. An interrupt routine contains a piece of code that the microcontroller on your board should execute whenever an event occurs. Take the air-conditioner example. Suppose it has the following temperature control settings: Switch off cooling whenever temperature reaches 18 degrees C. Now, there will be a temperature sensor that keeps measuring the temperature. Whenever it reports a temperature of 18 degrees Celsius, the normal code running on the AC microcontroller is interrupted, it executes the code to turn off cooling, and then the normal code ... Read More
In every language, generally, the first Hello World project is a simple program that prints "Hello World"! We will see what such a code would look like for Arduino. The below code will print "Hello World" on the screen every time your board is powered ON.Examplevoid setup() { Serial.begin(9600); Serial.print("Hello World!"); } void loop() { }However, this is not a very good choice of Hello World project for Arduino. We essentially use Arduino for firmware programming (in layperson terms, firmware is the permanent software inside any chip). Now, one characteristic of firmware is to do tasks repeatedly. That ... Read More