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[on:]

Hello,

I have a problem for driving a stepper motor out of python(blender). The stepper should make the same rotation as cube in Blender3D. I´m using Blender 2.63, Pyserial 2.6, Arduino Mega2560, a big easy driver and a 1A stepper motor with 200 steps.

Python code:

Code:

import bpy
import math
from math import degrees
import serial
ser = serial.Serial('COM5',115200,timeout=1)

def my_handler(scene):
    data = ''
    eulx = bpy.data.objects['Cube'].rotation_euler
    x = degrees(eulx.y)
    a = (x/360)*200
    data = bytes([int(a)])
    ser.write(data)
bpy.app.handlers.frame_change_post.append(my_handler)

Arduino code:

Code:

#include <AccelStepper.h>

int motorSpeed = 115200;
int motorAccel = 8000;

int motorDirPin = 9;
int motorStepPin = 8;

AccelStepper stepper(1, motorStepPin, motorDirPin);

void setup(){
  Serial.begin(115200);
  pinMode(5, OUTPUT);
  pinMode(6, OUTPUT);
  pinMode(7, OUTPUT);
  digitalWrite(5, LOW);
  digitalWrite(6, LOW);
  digitalWrite(7, LOW);
  stepper.setMaxSpeed(motorSpeed);
  stepper.setSpeed(motorSpeed);
  stepper.setAcceleration(motorAccel);
}

int num;

void loop()
{
  if (stepper.distanceToGo() == 0)
    num = Serial.read();
    stepper.moveTo(num);
    stepper.run();   
}

When I try this, the shaft moves and immediately moves back to its origin position. When I replace the "num" in the arduino code for testing, everything works fine (the shaft moves half of a full rotation).

Has anybody an idea why this could happen?

Thank you very much!

[Reply #1 on:]

What does the data you are writing out the serial port look like? Is it a byte or integer or string? Are you processing it correctly at the Arduino end? It sonds sort of like the motor is turning back to the ZERO position.

[Reply #2 on:]

Hi,

thank you for trying to help me. The output for the example above is:

Code:

>>>data = ''
>>>x = 180
>>>a = (x/360)*200
>>>print(a)
100
>>>data = bytes([int(a)])
>>>print(data)
b'd'

So b'd' is the data sent. This works perfectly for my servos....

Any idea why it won´t work on the steppers?

Thank you