If Statements , AND, OR, Equal & not Equal - Arduino

 This is all about "If Statements" in the Arduino world.

These are only executed , based on a condition

 

The if statement checks for a condition and executes the following statement or set of statements if the condition is 'true'.

 

https://www.arduino.cc/reference/en/language/structure/control-structure/if/

 

 

Check out this old circuit about pots:

+ Potentiometers - measuring voltages. 

 

 I'll be modifying this with a if statement.

 

 

The code:

----------------

// if statement exercise
// if voltage is above 4V, the LED lights

// set up variables

int myPin=A2;
int readVal;
float V2;
int dT=250;

int redPin=9;

void setup()
{
  Serial.begin(9600);
  pinMode(myPin,INPUT);
  pinMode(redPin,OUTPUT);
 
}

void loop()
{
  readVal=analogRead(myPin);
  V2=(5./1023.)*readVal;
  // converts to a voltage -- remember to place the decimal
  // points after the 5 & 1023 ... these may be floating points
 
  Serial.print("Potentiometer Voltage is ");
  Serial.println(V2);
 
  if(V2>4.0){
    digitalWrite(redPin, HIGH);
  }
  if (V2<4.0) {
    digitalWrite(redPin, LOW);
  }
 
  delay(dT);
}

------------------------------------

Here is a variation of the if statement using equal (==)

and not equal(!=)

 

 if(V2==5.0){
    digitalWrite(redPin, HIGH);
    // "==" is equal
  }
 
  if (V2!=5.0) {
    digitalWrite(redPin, LOW);
    // != is not equal

 

----------------------------------------------------------------------

 Compound Conditionals

You can also use AND , OR

 if(V2>2.0 && V2<3.0){
    digitalWrite(redPin, HIGH);
    // "&&" is and
  }
 
  if (V2<2 || V2>3) {
    digitalWrite(redPin, LOW);
    // "||" is OR
  }
 
  delay(dT);

 ----------------------

if you are combining great than and equal, you don't use "=="

eg:

 if(V2>=2.0 && V2<=3.0){
    digitalWrite(redPin, HIGH);
    // "&&" is and
  }
 
  if (V2<=2 || V2>=3) {
    digitalWrite(redPin, LOW);
    // "||" is OR

--------------------------------------------

 

 

Thanks to Paul McWhorter for the great video.

https://www.youtube.com/watch?v=ORNted-NgRM&t=11s

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