Serial connection from python to arduino Error!

Using Arduino Programming Questions
1

Hi,

I´m trying to set up a serial connection (USB) between a python programm and my arduino nano. I need to send two unsigned shorts like this {0x123,0x345} to get my galvos to work. This is my code:

Arduino side:

#include "Drawing.h"
#include "Objects.h"


unsigned short serialData[] = {0x000,0x000};
char hi, lo;


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


void Serial_Obj()
{
   if (Serial.available()>0){
    delay(50);
    
    //First byte for x-pos
    hi = Serial.read();
    lo = Serial.read();

    serialData[0] = (hi << 8) | lo;
   

    //Second byte for y-pos
    hi = Serial.read();
    lo = Serial.read();
    serialData[1] = (hi << 8) | lo;
       


    Drawing::drawObject(serialData, sizeof(draw_island)/4); //this is where I need to send coordinates


  }


void loop() {
   Serial_Obj();
}

And the python side:

import numpy as np
import time
import serial

arduinoData = serial.Serial('com6',9600, timeout=None)      #timeout weg?
x = 0
y = 160
x_ser = 0
y_ser = 0
beam_distance = 5   #distance in pixel
speed = 1          # speed in ms
resolution = 1280.
max_dez = 32767.
pixel = max_dez/resolution

array_object = np.random.randint(2, size=(1280, 960))

while y<=960:

    while x<=1280:
        if array_object[x,y] == 1:

            x_ser = round(x*pixel)
            y_ser = round((y+160)*pixel)
            
            arduinoData.write(x_ser.to_bytes(2, byteorder='big'))

            arduinoData.write(y_ser.to_bytes(2, byteorder='big'))
            
            time.sleep(speed)

        x=x+1
    x = 0
    y = y+beam_distance

y=0

Thanks a lot!!!

2

You left out something very very important.

You forgot to tell what the problem is.

3

What type of Arduino? Your variable sizes don’t match up with the normal UNO.

4

This Simple Python - Arduino demo should help get you started.

...R

5

Hi,

wow I really forgot that, sry:D

The scanner I send the data to, is supposted to scan one dot out of my random array for every delay (speed in ms). Instead every 5 seconds it scans 5 dots without the delay(delay of 5 seconds gives the same result). It´s really fast so that you see a rectangle combined with a triangle kind of shape (not what I want).

Robin2:
This Simple Python - Arduino demo should help get you started.

I think the idea of sending a start and end sign could fix my problem.

6

Ghostrider5:
I think the idea of sending a start and end sign could fix my problem.

I forgot to include the following link which may also help
Serial Input Basics

...R