Arduino: Switch Case

Sumber: https://docs.arduino.cc/built-in-examples/control-structures/SwitchCase

An if statement allows you to choose between two discrete options, TRUE or FALSE. When there are more than two options, you can use multiple if statements, or you can use the switch statement. Switch allows you to choose between several discrete options. This tutorial shows you how to use it to switch between four desired states of a photo resistor: really dark, dim, medium, and bright.

This program first reads the photoresistor. Then it uses the map() function to map its output to one of four values: 0, 1, 2, or 3. Finally, it uses the switch() statement to print one of four messages back to the computer depending on which of the four values is returned.

Hardware Required Arduino Board

photoresistor, or another analog sensor

10k ohm resistors

hook-up wires

breadboard

Circuit The photoresistor is connected to analog in pin 0 using a voltage divider circuit. A 10K ohm resistor makes up the other side of the voltage divider, running from Analog in 0 to ground. The analogRead() function returns a range of about 0 to 600 from this circuit in a reasonably lit indoor space.

circuit

Schematic schematic

/*

 Switch statement

 Demonstrates the use of a switch statement. The switch statement allows you
 to choose from among a set of discrete values of a variable. It's like a
 series of if statements.

 To see this sketch in action, put the board and sensor in a well-lit room,
 open the Serial Monitor, and move your hand gradually down over the sensor.

 The circuit:
 - photoresistor from analog in 0 to +5V
 - 10K resistor from analog in 0 to ground

 created 1 Jul 2009
 modified 9 Apr 2012
 by Tom Igoe

 This example code is in the public domain.

 https://www.arduino.cc/en/Tutorial/BuiltInExamples/SwitchCase

• /

// these constants won't change. They are the lowest and highest readings you // get from your sensor: const int sensorMin = 0; // sensor minimum, discovered through experiment const int sensorMax = 600; // sensor maximum, discovered through experiment

void setup() {

 // initialize serial communication:
 Serial.begin(9600);

}

void loop() {

 // read the sensor:
 int sensorReading = analogRead(A0);
 // map the sensor range to a range of four options:
 int range = map(sensorReading, sensorMin, sensorMax, 0, 3);

 // do something different depending on the range value:
 switch (range) {
   case 0:    // your hand is on the sensor
     Serial.println("dark");
     break;
   case 1:    // your hand is close to the sensor
     Serial.println("dim");
     break;
   case 2:    // your hand is a few inches from the sensor
     Serial.println("medium");
     break;
   case 3:    // your hand is nowhere near the sensor
     Serial.println("bright");
     break;
 }
 delay(1);        // delay in between reads for stability

}

Learn more You can find more basic tutorials in the built-in examples section.

You can also explore the language reference, a detailed collection of the Arduino programming language.

Last revision 2015/08/11 by SM

Referensi

• https://docs.arduino.cc/built-in-examples/control-structures/SwitchCase