Light source PWM regulation through labview

[adepressedstudent]

Hey,

I'm doing this project where the goal is to control the power of a light source through labview. I have both of those code but at the end of the day I can never contol the light anyone can help me ?

float labviewFLT = 0;
const byte numChars = 32;
char labviewSTR[numChars];
int pwm = 4; // assigns pin 4 to variable pwm
int t1 = 0;   // declares variable t1
int t2 = 0;   // declares variable t2
float a = 5;
float b = 1000;
int c = 1000;
boolean newData = false;

void setup() {
 Serial.begin(9600);
 pinMode(pwm,OUTPUT);
}

void loop() {
    static byte ndx = 0;
    char endMarker = '\n';
    char rc;
    
    while (Serial.available() > 0 && newData == false) {
        rc = Serial.read();

        if (rc != endMarker) {
            labviewSTR[ndx] = rc;
            ndx++;
            if (ndx >= numChars) {
                ndx = numChars - 1;
            }
        }
        else {
            labviewSTR[ndx] = '\0'; // terminate the string
            ndx = 0;
            newData = true;
        }
    }
    if (newData) {
      labviewFLT = atof(labviewSTR);
      t2  = labviewFLT/(a/b); // reads the voltage at A0 and saves in t2; // reads the voltage at A0 and saves in t2
      t1= c-t2;         // subtracts t2 from 1000 ans saves the result in t1
      digitalWrite(pwm, HIGH); // sets pin 12 HIGH
      delayMicroseconds(t1);   // waits for t1 uS (high time)
      digitalWrite(pwm, LOW);  // sets pin 12 LOW
      delayMicroseconds(t2);   // waits for t2 uS (low time)
      newData = false;
    }
    else {
      digitalWrite(pwm,LOW);
    }
}

And for labview :

I'm really sorry if this seems to be an obvious problem but I'm clearly not talented at electricity or programming
Thanks a lot

[flashko]

I don't know about labview, but your program does not generate PWM as you wrote. When receiving new data, your program only ONCE sets the pin high for a certain amount of time and then turns it off. Then it waits for new data and does nothing. If you want this pin to have a continuous signal, use the analogWrite() command and make sure the selected pin has hardware PWM - you didn't say what Arduino you're using, but the UNO version doesn't have PWM on pin 4, only on pins 3,5, 6, 9, 10 and 11.

[raschemmel]

FYI, digitalWrite is not an arduino PWM command. The correct command is analogWrite, as Flashko
pointed out.
Why are using digitalWrite ?
I know this is going to sound obvious , but if you are going to use an Arduino, wouldn't it be wise to
at LEAST due your due diligence and study the basics ? Read some tutorials, use the Arduino Reference page, SEARCH FOR "PWM" ON THE "Search FORUM " search bar ?
Posting here without doing the above is like saying "I really don't have time to learn anything, could
you just please tell me what to do ?" , is it not ?
(I call it like I see it)
Give this a read:
PWM LIGHT DIMMER