Getting trivial characters from serial port while printing to the LCD.

Projects Programming
1

Hello guys,
i have been having some troubles with getting data from serial ports. I have made a program that gives you the % CPU usage and RAM through the serial ports. And I am printing them to the LCD with Arduino UNO R3. The program sends "*", "/" and "-" for commands second line first line and remove commands respectively. For example program sends data to Arduino through the serial port like this;

"/" + "percentage usage" + "*" + "RAM usage" + "-"

Print should be like this;

"percentage usage"
"RAM usage"
("-" cleans the screen for the next data")

but i get this weird characters like in the attachment.

Here is my arduino code:

#include <LiquidCrystal_I2C.h>
#include <Wire.h>

LiquidCrystal_I2C lcd(0x27,16,2);


void setup() {
lcd.init();
lcd.backlight();
Serial.begin(9600);
}

void loop() {
 
  String content = "";
  char character;

  while(Serial.available()) {
      Serial.flush();
      
      character = Serial.read();
    //  Serial.flush();
      
      content.concat(character);
     // Serial.flush();
}
  

  if (content != "") {
   
    if (content == "/") {
  content = "";
  lcd.setCursor(0,0);
}

if (content == "*") {
  content = "";
  lcd.setCursor(0,1);
}
 
    lcd.print(content);
  }
 
    if (content == "-") {
    lcd.clear();
  }
  
}

If you guys can help me, i would appriciate all your affords. Thank you in advance.

FullSizeRender.jpg
FullSizeRender.jpg3264×2448 1 MB

2

Why are you using Serial.flush() ?

3

I don't know it sounds like a nice thing to write ;D

4

But it does not change anything.

5

I don't know it sounds like a nice thing to write

"I wandered lonely as a cloud" is a nice thing to write, but the C compiler is innoculated against nice things before it it is shipped.

6

AWOL:
"I wandered lonely as a cloud"

I always prefered "I walked about, a bit, on my own" :slight_smile:

7

Okay i removed the flushes so what else i can do now?

8

I suspect that you're sending the values you want printed, rather than a string representation of them.

Either that or you haven't set the same baud rate on your computer as you're using on the arduino.

9

Does the program on the PC side send the data exactly as you think it does? Send some mock data (e.g. cpu_usage = 0, 1, 48, 65; then same for RAM) and see if you can detect a pattern in the LCD output.

10

I just modified the code and it is working very nice but there is a little problem about refresh. Sometimes 2nd like does not appear. I think im gonna try some other methods for lcd.clean(); part. I will keep updating this post in order to help other people thay may having the same problem.

#include <LiquidCrystal_I2C.h>
#include <Wire.h>

LiquidCrystal_I2C lcd(0x27,16,2);


void setup() {
lcd.init();
lcd.backlight();
Serial.begin(9600);
}

void loop() {
char character;

while(Serial.available()){

  character = Serial.read();

  if(character == '+'){

    lcd.setCursor(0,0);
  }
  
  else if(character == '*'){

    lcd.setCursor(0,1);
  }
  
  else if(character == '-'){

    lcd.clear();
  }
  else 
  lcd.print(character);

}

}