I am trying to get data from Python to Arduino. In the serial monitor(Arduino Tools->serial monitor), i am receiving the data. When the data is sent from python, i am getting the message, "Error in getting the data"

I am using Arduino Mega.

void setup() {
  Serial.begin(9600); // Initialize serial communication at 9600 baud rate
}

void loop() {
  if (Serial.available()) {
    String message = Serial.readStringUntil('\n'); // Read message until newline
    Serial.println("Received message: " + message); // Send a response back to Python
  } else {
    Serial.println("Error in getting the data");
   }
}

import serial

SERIAL_PORT = "COM20"  # Replace with your Arduino's serial port
BAUD_RATE = 9600

with serial.Serial(SERIAL_PORT, BAUD_RATE, timeout=1) as ser:
  message = "Hello from Python!"
  ser.write(message.encode() + b'\n')  # Send message with newline

  while True:
    response = ser.readline().decode().strip()
    if response:
      print("Received from Arduino:", response)
      break  # Exit loop after receiving response

  print("Message sent and received successfully!")

 

You are extremely optimistic! You are expecting data to be available in line 6 immediately and if the data isn’t ready, you print “Error in getting the data”.

Realistically, if Seral.available() is false, you would just go back and see if it’s available later. You wouldn’t assume there’s an error.

 

Consider how long it takes to get a single 8-bit value across a 9600 baud serial link. That's ten bits (including start and stop and assuming you have no parity). That's about 1 ms for EACH character.

How many clock cycles is that?

 

You are trying to send serial data from Python while the Arduino port is already in use via the serial monitor in Arduino IDE. Close Arduino IDE serial monitor and run the Python code with Thonny. I edited your code a bit and it works for me.

void setup() {
  Serial.begin(9600); // Initialize serial communication at 9600 baud rate
}

void loop() {
  delay(1000);
  if (Serial.available()) {
    String message = Serial.readStringUntil('\n'); // Read message until newline
    Serial.println("Received message: " + message); // Send a response back to Python
  } else {
   }
}

import serial

SERIAL_PORT = "COM3"  # Replace with your Arduino's serial port
BAUD_RATE = 9600

with serial.Serial(SERIAL_PORT, BAUD_RATE, timeout=1) as ser:
  message = "Hello from Python!"
  #ser.write(message.encode() + b'\n')  # Send message with newline

  while True:
    ser.write(message.encode() + b'\n')  # Send message with newline
    response = ser.readline().decode().strip()
    if response:
      print("Received from Arduino:", response)
      break  # Exit loop after receiving response

 

You are trying to send serial data from Python while the Arduino port is already in use via the serial monitor in Arduino IDE. Close Arduino IDE serial monitor and run the Python code with Thonny. I edited your code a bit and it works for me.

void setup() {
  Serial.begin(9600); // Initialize serial communication at 9600 baud rate
}

void loop() {
  delay(1000);
  if (Serial.available()) {
    String message = Serial.readStringUntil('\n'); // Read message until newline
    Serial.println("Received message: " + message); // Send a response back to Python
  } else {
   }
}

import serial

SERIAL_PORT = "COM3"  # Replace with your Arduino's serial port
BAUD_RATE = 9600

with serial.Serial(SERIAL_PORT, BAUD_RATE, timeout=1) as ser:
  message = "Hello from Python!"
  #ser.write(message.encode() + b'\n')  # Send message with newline

  while True:
    ser.write(message.encode() + b'\n')  # Send message with newline
    response = ser.readline().decode().strip()
    if response:
      print("Received from Arduino:", response)
      break  # Exit loop after receiving response

View attachment 316651

Thank you. It is working.