jdz/gps01.py

#!/usr/bin/python
# -*- coding:utf-8 -*-
import RPi.GPIO as GPIO
import serial
import time, os
import csv
from datetime import datetime


# GPIO configuration
GPIO.setmode(GPIO.BCM)
GPIO.setwarnings(False)

ser = serial.Serial('/dev/ttyUSB3',115200)
ser.flushInput()

rec_buff = ''
time_count = 0

myhost = os.uname()[1]


# CSV file settings
csv_filename = f"gps_data_{myhost}.csv"
csv_headers = ["Timestamp", "Latitude", "Longitude"]

def convert_to_decimal(coord_str):
    coord = coord_str[:-2]
    direction = coord_str[-1]

    degrees = float(coord[:2] if direction in ['N', 'S'] else coord[:3])
    minutes = float(coord[2:] if direction in ['N', 'S'] else coord[3:])
    
    decimal = degrees + (minutes / 60)
    
    if direction in ['S', 'W']:
        decimal = -decimal
    
    return decimal

def parse_gps_data(gps_string):
    parts = gps_string.split(',')
    if len(parts) != 4:
        return "Invalid GPS data"
    
    lat = convert_to_decimal(parts[0] + ',' + parts[1])
    lon = convert_to_decimal(parts[2] + ',' + parts[3])
    
    return f"{lat:.6f}", f"{lon:.6f}"

def write_to_csv(lat, lon):
    timestamp = datetime.now().strftime("%Y-%m-%d %H:%M:%S")
    with open(csv_filename, mode='a', newline='') as file:
        writer = csv.writer(file)
        writer.writerow([timestamp, lat, lon])
    

def send_at(command,back,timeout):
    rec_buff = ''
    ser.write((command+'\r\n').encode())
    time.sleep(timeout)
    if ser.inWaiting():
        time.sleep(0.01)
        rec_buff = ser.read(ser.inWaiting())
    if rec_buff != '':
        if back not in rec_buff.decode():
            print(command + ' ERROR')
            print(command + ' back:\t' + rec_buff.decode())
            return 0
        else:
            gps_data = rec_buff.decode()[13:-36]
            print("Raw GPS data:", gps_data)
            lat, lon = parse_gps_data(gps_data)
            converted_gps = f"{lat}, {lon}"
            print("Converted GPS data for Google Maps:", converted_gps)
            current_time = datetime.datetime.now()
            write_to_csv(current_time, lat, lon)
            return 1
    else:
        print('GPS no está listo')
        return 0

def get_gps_position():
    rec_null = True
    answer = 0
    print('Iniciando GPS')
    rec_buff = ''
    send_at('AT+CGPS=1,1','OK',1)
    time.sleep(2)
    while rec_null:
        answer = send_at('AT+CGPSINFO','+CGPSINFO: ',1)
        client.publish("iiot/"+ myhost +"/gps", rec_buff, 0)
        if 1 == answer:
            answer = 0
            if ',,,,,,' in rec_buff:
                print('GPS no está listo')
                rec_null = False
                time.sleep(1)
        else:
            print('error %d'%answer)
            rec_buff = ''
            send_at('AT+CGPS=0','OK',1)
            return False
        time.sleep(1.5)


# Create CSV file with headers if it doesn't exist
        if not os.path.exists(csv_filename):
            with open(csv_filename, mode='w', newline='') as file:
                writer = csv.writer(file)
                writer.writerow([timestamp, lat, lon])
                writer.writerow(csv_headers)


try:
    get_gps_position()
  
except:
    if ser != None:
        ser.close()
    GPIO.cleanup()
    
if ser != None:
    ser.close()
    GPIO.cleanup()