ArduinO Learning

1. Map function

      map fuction in arduino

function:  
map(value,fromLow,fromHigh,toLow,toHigh);

Re-maps a number from one range to another range
- a value of fromLow would get mapped to toLow
- a value of fromHigh to toHigh
- value in between to values in between

It's Parameters

+value: the number to map
+fromLow: the Lower bound of the value's current range
+fromHigh: the Upper bound of the value's current range
+toLow: the Lower bound of the value's target range
+toHigh: the Upper bound of the value's target range

Example:

void setup() {}

void loop()
{
  int val = analogRead(0);
  val = map(val, 0, 1023, 0, 255);
  analogWrite(13, val);
}

fromLow to toLow (0 to 0);
fromHigh to toHigh (1023 to 255);

Note that the "lower bounds" of either range may be larger or smaller than the "upper bounds" so the map() function may be used to reverse a range of numbers, for example

y = map(x, 0, 1023, 255, 0);

The function also handles negative numbers well, so that this example

y = map(x, 1, 100, 0, -255);

is also valid and works well.

thank you! for watching