Arduino COM ERROR :( ...HELP SOS~~

Using Arduino Programming Questions
#1

ok guys i’ve settled this programming code problem…

but there is one more problem arise when i tried to upload to my arduino UNO…

avrdude: ser_open(): can’t open device “\.\COM5”: Access is denied.

i just combined the temperature reading code with the blynk example code. The blynk is showing online status but i just cant get the serial monitor to open…tried all the usb ports in my laptop still don’t help…

SOS…Please help and guide me

#include <SoftwareSerial.h>
SoftwareSerial DebugSerial (2,3); //RX , TX
#define BLYNK_PRINT DebugSerial
#include <BlynkSimpleStream.h>

char auth [] = "39a89ba968c74d20820a0e7431080527";
    //Declare the variables  
    int temp;  
    int temppin = 5;  
    int led1 = 7;  
    int led2 = 6; 

void setup ()
{
  DebugSerial.begin(9600);
  Serial.begin(9600);
  Blynk.begin(auth, Serial);
 


        pinMode(led1, OUTPUT);  
        pinMode(led2, OUTPUT);  
        Serial.begin(9600); //BaudRate  
      
    void loop()  
    
        temp = analogRead(temppin);  
        float t = (temp / 1024.0) * 5000;  
        float celsius = t / 10;  
        float farh = (celsius * 9) / 5 + 32;  
        //Celsius Temperature  
        Serial.print("Temperature =");  
        Serial.print(celsius);  
        Serial.print("°C");  
        Serial.println();  
        delay(1000);  
        if (celsius > 30)  
        {  
            digitalWrite(led2, HIGH);
            digitalWrite(led1, LOW);  
        }  
        else  
        {  
            digitalWrite(led2, LOW);
            digitalWrite(led1, HIGH);  
        }  
        if (celsius < 30)  
        {  
            digitalWrite(led1, HIGH);
            digitalWrite(led2, LOW);  
        }  
        else  
        {  
            digitalWrite(led2, HIGH);
            digitalWrite(led1, LOW);  
        }  
         
        {
          Blynk.run();
        }
        
}

i am using Blynk to monitor my LM35 sensor on Arduino Uno through USB… am i doing it right?

#2

Your code looks very poorly indented and this is your issue. Lean to always keep code correctly indented and many bugs will be evident

==> Press ctrl-T to indent your code and you’ll see something clearly misaligned for your functions... then look for the missing { or } (or both)

You also have two Serial.begin(9600);that’s one too many

#3

ALL THE ABOVE - PLUS A big hint... Take a look at how your loop() function is formed.

#4

Let us remember -- an Arduino Sketch always begins with the following two functions:

void setup()
{                                //opening brace

}                               //closing brace

void loop()
{                               //opening brace

}                               //closing brrace

Check that the formats of the setup() and loop functions of your sketch agree with the above.

There could be many more braces {}, parentheses (), and brackets [] in a program; but, they must be balanced. Balanced refers to the fact that when there is an opening brace/parenthesis/bracket, there must be a corresponding closing brace/parenthesis/bracket.

#5

ok guys i've settled this programming code problem..

but there is one more problem arise when i tried to upload to my arduino UNO..

avrdude: ser_open(): can't open device "\.\COM5": Access is denied.

i just combined the temperature reading code with the blynk example code. The blynk is showing online status but i just cant get the serial monitor to open..tried all the usb ports in my laptop still don't help...

SOS....Please help and guide me

#6

Has it ever work? Did you install necessary drivers ? Check usb cable Reboot your PC Ensure usb Port is correctly selected Ensure correct Arduino board is selected Try again

#7

J-M-L: Has it ever work? Did you install necessary drivers ? Check usb cable Reboot your PC Ensure usb Port is correctly selected Ensure correct Arduino board is selected Try again

1.) yup.. before i did anything for iot part, i've tested it on my circuit..the code works perfectly 2.) installed Blynk libraries and unzipped correctly as i am able to control the LED in arduino thru Blynk app but just that codes cant be uploaded to the arduino uno right now. 3.) this is something suspecious too but i am able to upload to the board correctly before iot part. 4.) done it...same case 5.) just COM port 5 are able to be selected.. 6.) arduino uno ..yes 7.) ok :(

#8

change USB port

#9

Sometimes, the following tricks work:

1. Plug-out and Plug-in the USB Cable. Check that Arduino/Genuino Uno on COM4/COMX message has appered at the bottom of the IDE Window.

2. IDE -->Tools and click. Check the following messages on the drop-down menu: (a) Board: "Arduino/Genuino Uno". If not, select from the Board Menu (b) Port: "COM4 (Arduino/Genuio Uno)"

3. Just Verify/Compile the sketch. Check that the sketch has been compiled.

4. Upload the sketch. If uploading problem (COM4/COMX is not found), goto the next step.

5. Device Manager ---> Ports (COM & LPT) ---> Arduino Uno (COM4) ---> Update Driver Software... (click) ---> Browse my computer for driver software (select) ---> Let me pick from a list of device drivers on my computer (select) ---> Arduino Uno (select) ---> next

6. If the Arduino Uno appears as other devices with (!) sign, then follow Step-5 (starting from Update Driver Software...) on that device.

Re-booting the PC also helps. Closing all the IDEs and launching only one IDE also helps.

#10

J-M-L: change USB port

hmm..i not sure why but when i pluck out all the wires from the board, it seems to be able to upload into it...now my blynk still cant show output of LM35 sensor data.

anyway i also tried pluck out VCC of LM35 , it seems to be able to uploaded into arduino board

#11

i was able to upload my code into arduino board and then i open the command prompt for blynk connection....now circuit is ok just that i cant view serial plotter where before this i can see "Temperature now is __ degree celsius"...it showing "Error opening serial port 'COM5'. (Port busy)" ..

#12