expected primary-expression before '>' token

Projects Programming
1 
//TMP36 Pin Variables
int sensorPin = 0; //the analog pin the TMP36's Vout (sense) pin is connected to
//the resolution is 10 mV / degree centigrade with a
//500 mV offset to allow for negative temperatures
int ledRed=5;
int ledGreen=11;
int ledYellow=8;
/* setup() - this function runs once when you turn your Arduino on. We initialize the serial connection with the computer
*/
void setup()
{
Serial.begin(9600); //Start the serial connection with the computer
//to view the result open the serial monitor 
pinMode (ledRed, OUTPUT);
pinMode (ledGreen, OUTPUT);
pinMode (ledYellow, OUTPUT);
}

void loop() // run over and over again
{
//getting the voltage reading from the temperature sensor
int reading = analogRead(sensorPin); 

// converting that reading to voltage, for 3.3v arduino use 3.3
float voltage = reading * 5.0 / 1024; 

// now print out the temperature
float temperatureC = (voltage - 0.5) * 100 ; //converting from 10 mv per degree wit 500 mV offset
//to degrees ((volatge - 500mV) times 100)
Serial.print(temperatureC); Serial.println(" degress C");

delay(1000); //waiting a second
if (temperatureC>=30)    //If the temperature reaches 30°C or more….
{
digitalWrite(ledRed,HIGH);  //...the piezo speakers beeps..
}
if (temperatureC<25)
{
digitalWrite (ledGreen,HIGH);
}
if (temperatureC <= 29 && >25);
{
digitalWrite (ledYellow,HIGH);
}
else     
{
digitalWrite(ledRed,LOW);   //...it is quiet.
digitalWrite (ledGreen,LOW);
digitalWrite (ledYellow,LOW);
}
}

Hi everyone, i'm new on this forum, and i hope you can help me
I was writing a program with arduino that controls the temperature, but when i putted the "if (temperatureC <= 29 && >25);" gives me the "expected primary-expression before '>' token" error...
how can I solve it? Thanks a lot :slight_smile:

3

if the temperature in deegres was greater than 25, the yellow led must light up

4

ricky0178:

if (temperatureC <= 29 && >25);

{
digitalWrite (ledYellow,HIGH);
}



Hi everyone, i'm new on this forum, and i hope you can help me
I was writing a program with arduino that controls the temperature, but when i putted the "if (temperatureC <= 29 && >25);" gives me the "expected primary-expression before '>' token" error...
how can I solve it? Thanks a lot :)

When using '&&' or '||' they can only combine complete expressions. ">25" is not a complete expression.

Second, the semicolon following the if (...) means that you do nothing. The following block gets executed regardless of the outcome of the test, as blocks are allowed everywhere regular statements are allowed.

Change to

if (temperatureC <= 29 && temperatureC > 25) {
    digitalWrite (ledYellow,HIGH);
}
5

Change to

As Delta_G showed you yesterday...

6

thanks everyone!