gps.py

import os
from pyb import wfi, UART, LED


def parse(line):
    try:
        sentence, *data, checksum = line.split(',')
    except ValueError:
        return

    if sentence == '$GPGGA':
        t, lat, lat_part, lng, lng_part, fix, sat_cnt, hdil, alt, _, geoid_height, _, _  = data

        if fix == '0':
            LED(2).off()
            LED(3).on()
        else:
            LED(3).off()
            LED(2).on()


def log_gps(uart, read_delay=100):
    led = LED(4)
    with open('/sd/gps.nmea', 'a') as f:
        print(file=f)

        try:
            while True:
                led.on()
                while uart.any():
                    line = str(uart.readline(), 'utf-8').rstrip()
                    print(line, file=f)
                    parse(line)
                    led.toggle()

                f.flush()
                led.off()
                wfi()
                #delay(read_delay)
        finally:
            led.off()
            LED(2).off()
            LED(3).off()
            os.sync()

    LED(1).on()


def run_gps_logger(uart_id, baudrate=9600):
    uart = UART(uart_id, baudrate)
    log_gps(uart, 10)