What is this strange letter in serial monitor?

Projects Programming
1

Hello.

I'm trying to send some integers from arduino to python by serial communication.

When I open the serial monitor, strange letter occurs first!

It seems Like ? notation but maybe rotating 180 degree. I'd like to attach screenshot but I don't know how to do...

When I read serialdata by python, it invokes errors telling that \xff385\r\n can't be decoded by ascii.

Here is the aruino code

int SAMPLINGRATE = 3000;

void setup() {
Serial.begin(9600);
}

void loop() {
 sendData();
}

void sendData(){
  for(int i=0; i<100; i++){
    Serial.println(analogRead(A0));
    delay(1/SAMPLINGRATE);
  }
}

and Here is python code

import serial

test = serial.Serial('COM3',9600)
result = []

while(True):
    if test.readable():
        fromArduino = test.readline().decode('ascii')
        print(fromArduino)

sketch version is 1.8.9
python 3.7.3
pyserial 3.4 in anaconda

Thanks!!

2

delay(1/SAMPLINGRATE); 1/3000 is zero.

3

Do you have the baud rate menu at the bottom right corner of Serial Monitor set to 9600?