Random

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random()

Description

Generates and returns a pseudo-random number.

Syntax

random(max) random(min, max)

• max: upper bound of the random value, exclusive
• min: lower bound of the random value, inclusive

Example

randNum = random(10);     //Generate a random number from 0-9
randNum2 = random(20,31); //Generate a random number from 20-31

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randomSeed()

Description

Initializes the random number generator with a 'seed' value. It is common to use the analogRead() value of an analog pin as the seed value.

Syntax

randomSeed(seed)

• seed: the number used to initialize the random number generator

Example

randomSeed(analogRead(A0));

Example Sketch

long randNum;

void setup() {
    randomSeed(analogRead(A0));
}

void loop() {
    randNum = random(100, 600);
    digitalWrite(13, HIGH,);
    delay(randNum)
    digitalWrite(13, LOW);
    delay(randNum);
}