nanovna_mag.py

from rotor import *
import time

import os
import shutil
from os import listdir
from os.path import isfile, join

import csv
import math

import subprocess

from watchdog.observers import Observer
from watchdog.events import FileSystemEventHandler

import threading


class nanovna_mag(FileSystemEventHandler):

    basepath = "/tmp"
    temp_folder = basepath+"/antenna_diagram"
    ts_folder = temp_folder+"/ts_temp"
    ts_file = ""

    _proc = 0
    _rotor = None
    _rotor_step = 1
    _continue_event = None
    antenna_diagram = []

    def __init__(self, rotor, rotor_step):
        # get rotor from main
        self._rotor = rotor
        self._rotor_step = rotor_step

        #init fs
        try:
            shutil.rmtree(self.temp_folder)
        except FileNotFoundError:
            print("removing folder failed, does not exist")
        #endtry

        os.mkdir(self.temp_folder)
        os.mkdir(self.ts_folder)

        # init event handler (watchdog)
        self._event_handler = self
        self._observer = Observer()
        self._observer.schedule(self._event_handler, path=self.ts_folder, recursive=False)
        self._observer.start()
    #enddef

    def __del__(self):
        self._observer.stop()

    def start(self, freq):
        self._proc = subprocess.Popen(["python3", "./nanovna-saver/nanovna-saver.py", "-o", self.ts_folder, "-f", str(freq * 1000000), "-t", str((freq * 1000000) + 1000), "-i"], 
                                      stdout=subprocess.DEVNULL)
        self._continue_event = threading.Event()
    #enddef
    
    def stop(self):
        self._proc.terminate()
    #enddef

    def on_created(self, event):
        #print("on_created", event.src_path)

        mag_array = []

        file_ok = False
        while not file_ok:
            # read touchstone file and calculate magnitude of S21 for all sweep points
            with open(event.src_path, newline='') as csvfile:
                reader = csv.reader(csvfile, delimiter=' ')
                for row in reader:
                    #print(f"row = '{row}'")
                    if row[0] != '#':
                        mag = math.sqrt(math.pow(float(row[4]), 2) + math.pow(float(row[5]), 2))
                        mag_array.append(mag)
                #endfor
            #endwith
            # retry until file has correct length (101 lines)
            if len(mag_array) == 101:
                file_ok=True
            else:
                mag_array=[]
            #endif
        #endfor

        # calculate average magnitude -> we want one value for one step
        avg = 0
        for i in mag_array:
            avg = avg + i
        avg = avg / len(mag_array)

        az = self._rotor.get_azimuth()
        print(f"{az} {avg}")
        self.antenna_diagram.append([az, avg])

        try:
            self._rotor.step_azimuth(self._rotor_step)
        except RotorDegreeOutOfRange:
            print("Rotor at end, stopping")
            self._continue_event.set()
        #endtry
    #enddef

    def wait_for_continue(self):
        self._continue_event.wait()
    #enddef
#endclass