107 lines
3.1 KiB
Python
107 lines
3.1 KiB
Python
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#!/usr/bin/python
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# -*- coding:utf-8 -*-
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import RPi.GPIO as GPIO
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import serial
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import time
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import os
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import csv
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from datetime import datetime
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import pynmea2
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# GPIO configuration
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GPIO.setmode(GPIO.BCM)
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GPIO.setwarnings(False)
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ser = serial.Serial('/dev/ttyUSB3', 115200)
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ser.flushInput()
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myhost = os.uname()[1]
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# CSV file settings
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csv_filename = f"gps_data_{myhost}.csv"
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csv_headers = ["Timestamp", "Latitude", "Longitude"]
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def parse_gps_data(gps_string):
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try:
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msg = pynmea2.parse(gps_string)
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print(f"Parsed message type: {type(msg).__name__}")
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if hasattr(msg, 'latitude') and hasattr(msg, 'longitude'):
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return f"{msg.latitude:.6f}", f"{msg.longitude:.6f}"
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else:
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print(f"Message doesn't contain lat/lon. Available attributes: {msg.fields}")
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except pynmea2.ParseError as e:
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print(f"Parse error: {e}")
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return None, None
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def write_to_csv(lat, lon):
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timestamp = datetime.now().strftime("%Y-%m-%d %H:%M:%S")
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with open(csv_filename, mode='a', newline='') as file:
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writer = csv.writer(file)
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writer.writerow([timestamp, lat, lon])
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time.sleep(12)
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def send_at(command, back, timeout):
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print(f"Sending command: {command}")
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ser.write((command + '\r\n').encode())
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time.sleep(timeout)
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if ser.inWaiting():
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time.sleep(0.01)
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rec_buff = ser.read(ser.inWaiting()).decode()
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print(f"Received data: {rec_buff}")
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if back not in rec_buff:
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print(command + ' ERROR')
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print(command + ' back:\t' + rec_buff)
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return 0
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else:
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print("Raw GPS data:", rec_buff)
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gps_sentences = rec_buff.split('\r\n')
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for sentence in gps_sentences:
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print(f"Processing sentence: {sentence}")
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if sentence.startswith('$'):
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lat, lon = parse_gps_data(sentence)
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if lat and lon:
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print(f"Valid GPS data found: {lat}, {lon}")
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write_to_csv(lat, lon)
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return 1
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print('No valid GPS data found in this response')
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return 0
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else:
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print('No data received from GPS')
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return 0
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def get_gps_position():
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print('Starting GPS')
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send_at('AT+CGPS=1,1', 'OK', 1)
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time.sleep(2)
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attempts = 0
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max_attempts = 10
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while attempts < max_attempts:
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print(f"Attempt {attempts + 1} of {max_attempts}")
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answer = send_at('AT+CGPSINFO', '+CGPSINFO:', 1)
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if answer == 1:
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print("Valid GPS data received and processed")
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break
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else:
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print('Waiting for GPS fix...')
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attempts += 1
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time.sleep(2)
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if attempts == max_attempts:
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print("Max attempts reached. GPS fix not obtained.")
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# Create CSV file with headers if it doesn't exist
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if not os.path.exists(csv_filename):
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with open(csv_filename, mode='w', newline='') as file:
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writer = csv.writer(file)
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writer.writerow(csv_headers)
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try:
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get_gps_position()
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except Exception as e:
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print(f"Error: {e}")
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finally:
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if ser:
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ser.close()
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GPIO.cleanup()
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