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Articles on Trending Technologies
Technical articles with clear explanations and examples
Timers in Arduino Uno
As discussed earlier, Arduino Uno has 3 timers: Timer0, Timer1 and Timer2. Timer0 and Timer2 are 8-bit counters (they count from 0 to 255), while Timer1 is a 16-bit counter (it counts from 0 to 65535). Internally, Timer0 is used for the millis() function, and therefore, it is recommended not to mess with it. You can use Timer1 and Timer2 for your custom requirements.Note that the clock frequency of Arduino Uno is 16 MHz. Therefore, no timer can have intervals shorter than (1/16000000). However, for most applications, you would want longer intervals (lower frequencies). In other words, you would want ...
Read MoreTimers in Arduino
Every microcontroller has one or more timers that help the users perform tasks at precise intervals. Arduino Uno, for example, has 3 timers: Timer0, Timer1 and Timer2. Other boards may have the same or different number of timers, which you can find from the datasheet of that board/ microcontroller. What are timers?Timers are essentially counters. Let me give you a simple example. Say you want to trigger a task every 5 seconds. Now, if you have a counter which can count from 0 to 255, then if you somehow adjust the rate of counting such that it finishes counting exactly in ...
Read MoreDifference between float and double in Arduino
FloatFloating point numbers are stored using 4 bytes (32 bits).Their max value can be 3.4028235E+38 and their min value can be -3.4028235E+38.They have a precision of about 6-7 decimal places.DoubleWhile on several platforms, double has more precision than float. However, on most Arduino boards (Uno and many other ATmega boards), double has the same size as float. Arduino Due is an exception, wherein double has a size of 8 bytes (compared to 4 bytes of float).On the boards where double is stored using 8 bytes, the max value can be 1.7*10^308 and the min value can be -1.7*10^308. On the ...
Read MoreDifference between signed and unsigned integer in Arduino
When you define an integer, it is signed by default. In other words, it can accept both positive and negative values. Unsigned integers, as the name suggests, accept only positive values. Therefore, they have a higher range.If you are using a board that uses two bytes (16 bits) to represent an integer, then the maximum range you would get for an unsigned integer is 0 to 65535 (216-1).However, when representing signed integers, the range would be -32767 to +32767. Note that 32767 corresponds to (215 -1). As you can see, the most significant bit seems to be out of action. ...
Read MoreDefining new functions in Arduino
Defining new functions in Arduino is equivalent to defining the functions in C.The syntax is −Syntaxreturn_type function_name(arg_type arg)The only difference is that in C, the function needs to be declared at the top, if it is invoked before its definition. No such constraint exists in Arduino. The following code demonstrates this −Examplevoid setup() { Serial.begin(9600); Serial.println(); } void loop() { // put your main code here, to run repeatedly: for (int i = 0; i < 10; i++) { long int w = square(i); Serial.println(w); delay(1000); ...
Read MoreConvert string to lowercase or uppercase in Arduino
In order to convert a string to lower/upper case, the in-built .toLowerCase() and .toUpperCase() functions can be used.Note: These functions change the original string itself, and don't return a new string with the changes.The implementation is shown below −Examplevoid setup() { Serial.begin(9600); Serial.println(); String s1 = "Hello World"; Serial.println(s1); s1.toLowerCase(); Serial.println(s1); s1.toUpperCase(); Serial.println(s1); } void loop() { // put your main code here, to run repeatedly: }The corresponding Serial Monitor output is −OutputAs you can see, the changes have been made in s1 itself. The return of .toUpperCase() and .toLowerCase() is void.
Read MoreReplace characters in a string in Arduino
The .replace() function in Arduino allows you to replace a character or a substring with another character/substring in Arduino.Note: This function replaces substrings in the original string itself, and does not return a new string containing the changes.Examples are given in the code below −Examplevoid setup() { Serial.begin(9600); Serial.println(); String s1 = "Hello World"; Serial.println(s1); s1.replace('e', 'a'); Serial.println(s1); s1 = "Hello World"; s1.replace("ll", "gg"); Serial.println(s1); s1 = "Hello World"; s1.replace("li", "gg"); Serial.println(s1); } void loop() { // put your main code here, to run ...
Read MoreConvert string to integer/ float in Arduino
In order to convert a string to an integer or a float, the .toInt() and .toFloat() functions can be used. Of course, the string should actually correspond to the integer or floating-point value. For instance, "1.87" can be converted to float. But it doesn't make sense to convert "Hello" to float. The below example code illustrates the conversions −Examplevoid setup() { Serial.begin(9600); Serial.println(); // put your setup code here, to run once: String s1 = "235"; String s2 = "1.56"; String s3 = "Hello"; int i1 = s1.toInt(); int i2 = s2.toInt(); ...
Read MoreConcatenate strings in Arduino
String concatenation in Arduino is quite straightforward and also robust. You simply use the + operator to join strings. However, it doesn't end with joining two strings. You can concatenate characters, and even integers and floats to strings (Arduino converts the integers and floating-point numbers to string internally). Examples can be seen in the below code.Examplevoid setup() { Serial.begin(9600); Serial.println(); // put your setup code here, to run once: String s1 = "Hello "; String s2 = "Bond!"; String s3 = s1 + s2; Serial.println(s3); s3 = s1 + 7; Serial.println(s3); ...
Read MoreConvert character array to string in Arduino
In order to convert a character array to a string, the String() constructor can be used. An example is shown below −Examplevoid setup() { // put your setup code here, to run once: Serial.begin(9600); Serial.println(); char buf[10] = "Hello!"; Serial.print("Char array: "); Serial.println(buf); String s = String(buf); Serial.print("String: "); Serial.println(s); } void loop() { // put your main code here, to run repeatedly: }The output of the Serial monitor is shown below −Output
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