Arduino Random Number

To generate random numbers, you can use the Arduino random number function. We have two functions:

• randomSeed(seed)
• random()

randomSeed(seed)

The randomSeed (seed) function resets Arduino's pseudo-random number generator. /b10> Although the distribution of the numbers returned by Random() is inherently random, the order is predictable. Y ou should reset the generator to a random value. /b12> If you have an unnected analog pin, it may pick up random noise from your surroundings. /b13> These may be radio waves, cosmic rays, electromagnetic interference from mobile phones, fluorescent lights, etc.

Example

randomSeed(analogRead(5)); // randomize using noise from analog pin 5

random()

The random function generates pseudo-random numbers. /b10> Here's the syntax.

random() syntax

long random(max) // it generate random numbers from 0 to max
long random(min, max) // it generate random numbers from min to max

Example

long randNumber;

void setup() {
   Serial.begin(9600);
   // if analog input pin 0 is unconnected, random analog
   // noise will cause the call to randomSeed() to generate
   // different seed numbers each time the sketch runs.
   // randomSeed() will then shuffle the random function.
   randomSeed(analogRead(0));
}

void loop() {
   // print a random number from 0 to 299
   Serial.print("random1=");
   randNumber = random(300);
   Serial.println(randNumber); // print a random number from 0to 299
   Serial.print("random2=");
   randNumber = random(10, 20);// print a random number from 10 to 19
   Serial.println (randNumber);
   delay(50);
}

Let's revisit our knowledge of some basic concepts, such as bits and bytes.

Bit (bit)

Bits are just binary numbers.

• The binary system uses two numbers, 0 and 1.

• Similar to a hedding digital system, the number of digits does not have the same value, and the "meaning" of a bit depends on its position in the binary number. /b10> For example, the numbers in the hedding number 666 are the same, but have different values.

Bytes

A byte consists of eight bits.

• If a bit is a number, logically bytes represent numbers.

• You can perform all mathematical operations on them.

• Numbers in a byte do not have the same meaning.

• The far left bit has a maximum value called the most effective bit (MSB).

• The far right bit has a minimum value and is therefore called the lowest valid bit (LSB).

• Since eight 0s and 1s of a byte can be combined in 256 different ways, the maximum number of octals that can be represented by one byte is 255 (a combination represents zero).