1  # Simple GPS datalogging demonstration.
 2  # This example uses the GPS library and to read raw NMEA sentences
 3  # over I2C or UART from the GPS unit and dumps them to a file on an SD card
 4  # (recommended), microcontroller internal storage (be careful as only a few
 5  # kilobytes are available), or to a filesystem.
 6  # If you are using a microcontroller, before writing to internal storage you
 7  #  MUST carefully follow the steps in this guide to enable writes to the
 8  # internal filesystem:
 9  #  https://learn.adafruit.com/adafruit-ultimate-gps-featherwing/circuitpython-library
10  import board
11  import busio
12  import adafruit_gps
13  
14  # Path to the file to log GPS data.  By default this will be appended to
15  # which means new lines are added at the end and all old data is kept.
16  # Change this path to point at internal storage (like '/gps.txt') or SD
17  # card mounted storage ('/sd/gps.txt') as desired.
18  LOG_FILE = "gps.txt"  # Example for writing to internal path gps.txt
19  
20  # File more for opening the log file.  Mode 'ab' means append or add new lines
21  # to the end of the file rather than erasing it and starting over.  If you'd
22  # like to erase the file and start clean each time use the value 'wb' instead.
23  LOG_MODE = "ab"
24  
25  # If writing to SD card on a microcontroller customize and uncomment these
26  # lines to import the necessary library and initialize the SD card:
27  # NOT for use with a single board computer like Raspberry Pi!
28  """
29  import adafruit_sdcard
30  import digitalio
31  import storage
32  
33  SD_CS_PIN = board.D10  # CS for SD card using Adalogger Featherwing
34  spi = busio.SPI(board.SCK, MOSI=board.MOSI, MISO=board.MISO)
35  sd_cs = digitalio.DigitalInOut(SD_CS_PIN)
36  sdcard = adafruit_sdcard.SDCard(spi, sd_cs)
37  vfs = storage.VfsFat(sdcard)
38  storage.mount(vfs, '/sd')    # Mount SD card under '/sd' path in filesystem.
39  LOG_FILE = '/sd/gps.txt'     # Example for writing to SD card path /sd/gps.txt
40  """
41  
42  # Create a serial connection for the GPS connection using default speed and
43  # a slightly higher timeout (GPS modules typically update once a second).
44  # These are the defaults you should use for the GPS FeatherWing.
45  # For other boards set RX = GPS module TX, and TX = GPS module RX pins.
46  uart = busio.UART(board.TX, board.RX, baudrate=9600, timeout=10)
47  
48  # If using a USB/Serial converter, use pyserial and update the serial
49  # port name to match the serial connection for the GPS!
50  # import serial
51  # uart = serial.Serial("/dev/ttyUSB0", baudrate=9600, timeout=10)
52  
53  # If using I2C, we'll create an I2C interface to talk to using default pins
54  # i2c = board.I2C()
55  
56  # Create a GPS module instance.
57  gps = adafruit_gps.GPS(uart)  # Use UART/pyserial
58  # gps = adafruit_gps.GPS_GtopI2C(i2c)  # Use I2C interface
59  
60  # Main loop just reads data from the GPS module and writes it back out to
61  # the output file while also printing to serial output.
62  with open(LOG_FILE, LOG_MODE) as outfile:
63      while True:
64          sentence = gps.readline()
65          if not sentence:
66              continue
67          print(str(sentence, "ascii").strip())
68          outfile.write(sentence)
69          outfile.flush()