map() function in Arduino??

What is the map() function in Arduino, why do we need a map function in Arduino, how to use the map function in Arduino & what map function in code does?? Are some questions that may arise in your mind while programming an Arduino??.

Hello guys! Welcome back to my blog. Today we are going to see the Arduino map function. so let’s begin.

What is the map() function in Arduino??

The map function in Arduino is a very important function in the calculation, mapping values, and scaling. The map function is used to scale values from one range to another range, to understand it better we will look at an example. Arduino map reduces to complex calculation in a code

We have a potentiometer and servo-motor we want our servo motor to rotate as we spin the potentiometer but the problem is that potentiometer gives us values 0 to 1023 and the servo motor rotates between 0 ° to 180 °. Now the question comes of how to scale up these two values to give precise output.

So we have x1=0, x2 = 1023 and y1 = 0, y2 = 180

Slope (m) = (y2-y1) / (x2-x1)

                = (180 – 0) / (1023 – 0)

  Slope (m)    = 180/1023

y – y1 = m (x - x1)

y = (180 / 1023) * x

Where x represents potentiometer values and y represents angle for servo motor. This equation will give us scale-up values between the potentiometer and servo motor.

Servo.write(y)

The value that we will get from y will be passed as a parameter in the servo write function which will drive the motor to the desired position as per the rotation of the potentiometer.

We will use float as a data type store value as values can be in decimal form also we are using floating point math.

Now for each such application where mapping of two numbers is required, finding slopes and calculation can be more time-consuming also calculation mistakes may be due to human may. So to eliminate such a long lengthy process we have a map() function in which we have to pass parameters. The map function takes 5 parameters such as value to be mapped, from low, from high, to low, to high. our map function also takes a negative number

map(value, from low, from high, to low, to high);

int angle = map(y,0,1023,0,180);

servo.Write(angle);

Example of map() function -

Controlling servo motor using Potentiometer using map() function

Code - 

#include <Servo.h>   // includes servo in-built library

Servo myservo;      // create servo object to control a servo

int potentiometer_pin = A0;

int potnetiometer_value;

void setup()

{

 Serial.begin(115200);

 pinMode(potentiometer_pin,INPUT);

   myservo.attach(9);   // connect signal pin of servo to pin no 12 of Arduino

}

void loop() 

{

 potnetiometer_value = analogRead(potentiometer_pin);

 // map(value, from low, from high, to low, to high);

  int angle = map(potnetiometer_value,0,1023,0,180);

  myservo.write(angle);          

  int read_angle = myservo.read();

  Serial.print("Servo Angle : ");

  Serial.print(read_angle);

  Serial.println(" deg ");

  delay(100);

}

Output - 

Now we used the serial monitor to observe the output. To open up the serial monitor, click on Tools > Serial Monitor or use the shortcut (SHIFT + CONTROL + M).  You can see the servo motor rotates with reference to the rotating knob of the potentiometer. here we have displayed various angles according to the rotation of knob of potentiometer”. the rotation of the knob can be in a clockwise or anti-clockwise direction which will drive the servo motor in the same direction. 

Conclusion –

Today we learn about the map Arduino function, where to use the map() function, how to use the Arduino map function, what the map() function does in Arduino, syntax, and the parameters of the map() function. we have seen an example of the map() function using a servo motor and potentiometer.

"I hope you find this IoT blog very helpful to you. In the upcoming lesson, we will see more about IoT sensors till then bye. See you all in my next blog."