sending numbers to arduino via python

Projects Interfacing w/ Software on the Computer
1

Hi -
I figured out how to send numbers from 0-9 to the arduino from python using Serial.read()-'0' . Is there a simple way to instead send a value larger than 0-9 to the arduino. Right now I turn on an LED to monitor whether the it is working. My plan is to turn on a stepper motor for a certain number of iterations. I want python to send the number of iterations to the arduino. Then I can assign that value (such as 32500) to the iteration counter that controls the motor. FYI I am a new to programming and dont have a great grasp of integers,bytes,strings, etc.

Heres the python code:

import serial
import time

arduino = serial.Serial(2, 9600, timeout = 1)
time.sleep(2)

while 1:
    
    command = str.encode('1')
    arduino.write(command)   
    time.sleep(1.5)

and the Arduino Code:

int led = 4;
int state = 0;

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

void loop() {
  if (Serial.available() > 0) {
      state = Serial.read()- '0';
     
      if  (state == 1){
      digitalWrite(led, HIGH);
      delay(100);
      digitalWrite(led, LOW);
      Serial.println(state);
      }

    while (Serial.available() > 0)
    {
      Serial.read();
    }
  }

}
2 
    command = str.encode('1')

What type is command supposed to be? What does encode do? Why do you think you need to encode anything?

    while (Serial.available() > 0)
    {
      Serial.read();
    }

You sent one character. You read one character. Why do you think that you need to dump random amounts of unread data?

3

The examples in serial input basics are simple reliable ways for the Arduino to receive data.

You may also be interested in this Python-Arduino demo.

...R