map() で値を新しい範囲に変換する

A 0 to 1023 reading rarely matches what you need. Often you want a percentage or an angle, not a raw sensor count.

The map function rescales a number from one range into another. It does the proportional math so you do not have to.

You give map five things: the value, plus the low and high of its current range and the low and high of the target range.

To turn a knob into 0 to 100 percent, map from the analog range to a percent range. The result reads like a volume dial.

Servos expect 0 to 180. Map a knob into that range and the reading becomes a usable angle for the motor.

The map function works in integers, so it returns whole numbers and drops the fraction. That is fine for most controls.

Set the target low above the high to invert the output. Now turning the knob right makes the result go down.

The map function will go past your limits if the input does. Use constrain afterward to keep the result safely inside bounds.

Targets can be negative, like -50 to 50 for a centered control. The map math handles that direction with no extra effort.

Pair map with PWM later to set brightness. A knob can scale neatly into the 0 to 255 range an LED dimmer expects.

You will reach for map constantly: percentages, angles, ranges, and more. It turns raw sensor data into meaningful numbers.

What is the job of the map function?

You learned map rescales a value between ranges using five arguments. Pair it with constrain to clamp results into safe bounds.