Getting Started with Arduino

MATH FUNCTIONS

Arduino includes many common mathematical and trigonometric functions:

min(x, y)

Returns the smaller of x and y.

Example:

val = min(10,20); // val is now 10

max(x, y)

Returns the larger of x and y.

Example:

val = max(10,20); // val is now 20

abs(x)

Returns the absolute value of x, which turns negative numbers into positive. If x is 5 it will return 5, but if x is –5, it will still return 5.

Example:

val = abs(-5); // val is now 5

constrain(x, a, b)

Returns the value of x, constrained between a and b. If x is less than a, it will just return a and if x is greater than b, it will just return b.

Example:

val = constrain(analogRead(0), 0, 255); // reject values bigger than 255

map(value, fromLow, fromHigh, toLow, toHigh)

Maps a value in the range fromLow and maxLow to the range toLow and toHigh. Very useful to process values from analogue sensors.

Example:

val = map(analogRead(0),0,1023,100, 200); // maps the value of
                                          // analog 0 to a value
                                          // between 100 and 200

double pow(base, exponent)

Returns the result of raising a number (base) to a value (exponent).

Example:

double x = pow(y, 32); // sets x to y raised to the 32nd power

double sqrt(x)

Returns the square root of a number.

Example:

double a = sqrt(1138); // approximately 33.73425674438

double sin(rad)

Returns the sine of an angle specified in radians.

Example:

double sine = sin(2); // approximately 0.90929737091

double cos(rad)

Returns the cosine of an angle specified in radians.

Example:

double cosine = cos(2); // approximately -0.41614685058

double ...