Raspberry Pi Pico GPS Tracker Using NEO-6M & OLED Display

Introduction

This guide will help you to build a Pico GPS tracker using the NEO-6M GPS module and OLED display. You’ll learn how to wire the components together and write a Micropython script to read data from the GPS module and display it on the OLED display.

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Global Positioning System, or GPS, technology allows accurate Tracking of residents, assets, and units. GPS allows exact location determination, route optimization, asset security, routine tracking, and real-time monitoring. this project allows you to create a portable GPS tracking device that displays accurate location coordinates on the OLED screen.

Required Material

Raspberry Pi Pico
NEO-6M GPS Module
OLED Display
Jumper Wires
Breadboard (optional)

Raspberry Pi Pico

The Raspberry Pi Pico is a small microcontroller board based on the RP2040 microcontroller chip. It provides GPIO pins for connecting and controlling multiple electronic components. The Pico runs multiple languages, including MicroPython and C/C++, making programming and interacting with many features easy.

Raspberry Pi Pico, is a highly capable microcontroller featuring dual-core ARM Cortex-M0+ processors clocked at 133MHz. It has 256KB of RAM and 2MB of onboard QSPI Flash memory for storing code and data. With 30 GPIO pins. which offers multi-interfacing options, including SPI, I2C, UART, ADC, and PWM channels.

NEO-6M GPS Module

NEO-6M GPS module is a high-performance, highly reliable GPS receiver. The module receives signals from GPS satellites and It uses the NMEA protocol to transmit GPS information, such as latitude, longitude, altitude, and satellite status and time.

Through UART communication, the module provides accurate GPS information for applications such as navigation, tracking, and geolocation.

NEO-6M GPS module Specifications

5Hz position update rate
Operating temperature range: -40°C to 85°C
UART TTL socket for easy communication
EEPROM for saving configuration settings
Rechargeable backup battery
Fast start times: 38 seconds cold start, 1-second hot start
Power Supply: 3.3V~5V
Configurable baud rates (4800 to 115200, default 9600)
SuperSense® Indoor GPS with -162 dBm tracking sensitivity
Support for SBAS (WAAS, EGNOS, MSAS, GAGAN)
Separated 18x18mm GPS antenna

Pinout of NEO-6M GPS Module

The common pinout of the NEO-6M GPS module includes VCC (power supply), GND (ground), TX (UART transmit), and RX (UART receive).

0.96″ OLED Display

The 0.96″ OLED (Organic Light-Emitting Diode) Display measures 0.96 inches diagonally. It is a small-sized display commonly used in electronic devices and DIY projects. check out How To Use SSD1306 Oled Display With Raspberry Pi Pico

0.96″ OLED display typically offers a resolution of 128×64 pixels or similar, allowing for the display of text, graphics, and simple images. It is used to show information such as sensor readings, notifications, or menu options in a compact and visual.

The OLED display is used to show the GPS data received from the NEO-6M module. It can show information such as latitude, and longitude details about the location.

Interfacing NEO-6M GPS Module with Raspberry Pi Pico W & OLED Display

GPS VCC to Pico 3.3V pin for power.
GPS GND to Pico GND pin for ground reference.
GPS TX to Pico GP5 pin for receiving data.
GPS RX to Pico GP4 pin for transmitting data.

Connect the OLED Display SDA SCL Pin to Pico GP14 & GP15 Pin. You can power the OLED Display using the 3.3V & GND pin of Pico. Hence the hardware setup & connections for Raspberry Pi Pico GPS Tracker is ready.

Code & Librires

The code and libraries for the project are divided into three parts.

micropyGPS.py

The first part consists of the library for the GPS module, which handles communication with the NEO-6M GPS module and provides functions for retrieving GPS data.

"""
# MicropyGPS - a GPS NMEA sentence parser for Micropython/Python 3.X
# Copyright (c) 2017 Michael Calvin McCoy (calvin.mccoy@protonmail.com)
# The MIT License (MIT) - see LICENSE file
""" 

# TODO:
# Time Since First Fix
# Distance/Time to Target
# More Helper Functions
# Dynamically limit sentences types to parse

from math import floor, modf

# Import utime or time for fix time handling
try:
    # Assume running on MicroPython
    import utime
except ImportError:
    # Otherwise default to time module for non-embedded implementations
    # Should still support millisecond resolution.
    import time


class MicropyGPS(object):
    """GPS NMEA Sentence Parser. Creates object that stores all relevant GPS data and statistics.
    Parses sentences one character at a time using update(). """

    # Max Number of Characters a valid sentence can be (based on GGA sentence)
    SENTENCE_LIMIT = 90
    __HEMISPHERES = ('N', 'S', 'E', 'W')
    __NO_FIX = 1
    __FIX_2D = 2
    __FIX_3D = 3
    __DIRECTIONS = ('N', 'NNE', 'NE', 'ENE', 'E', 'ESE', 'SE', 'SSE', 'S', 'SSW', 'SW', 'WSW', 'W',
                    'WNW', 'NW', 'NNW')
    __MONTHS = ('January', 'February', 'March', 'April', 'May',
                'June', 'July', 'August', 'September', 'October',
                'November', 'December')

    def __init__(self, local_offset=0, location_formatting='ddm'):
        """
        Setup GPS Object Status Flags, Internal Data Registers, etc
            local_offset (int): Timzone Difference to UTC
            location_formatting (str): Style For Presenting Longitude/Latitude:
                                       Decimal Degree Minute (ddm) - 40° 26.767′ N
                                       Degrees Minutes Seconds (dms) - 40° 26′ 46″ N
                                       Decimal Degrees (dd) - 40.446° N
        """

        #####################
        # Object Status Flags
        self.sentence_active = False
        self.active_segment = 0
        self.process_crc = False
        self.gps_segments = []
        self.crc_xor = 0
        self.char_count = 0
        self.fix_time = 0

        #####################
        # Sentence Statistics
        self.crc_fails = 0
        self.clean_sentences = 0
        self.parsed_sentences = 0

        #####################
        # Logging Related
        self.log_handle = None
        self.log_en = False

        #####################
        # Data From Sentences
        # Time
        self.timestamp = [0, 0, 0.0]
        self.date = [0, 0, 0]
        self.local_offset = local_offset

        # Position/Motion
        self._latitude = [0, 0.0, 'N']
        self._longitude = [0, 0.0, 'W']
        self.coord_format = location_formatting
        self.speed = [0.0, 0.0, 0.0]
        self.course = 0.0
        self.altitude = 0.0
        self.geoid_height = 0.0

        # GPS Info
        self.satellites_in_view = 0
        self.satellites_in_use = 0
        self.satellites_used = []
        self.last_sv_sentence = 0
        self.total_sv_sentences = 0
        self.satellite_data = dict()
        self.hdop = 0.0
        self.pdop = 0.0
        self.vdop = 0.0
        self.valid = False
        self.fix_stat = 0
        self.fix_type = 1

    ########################################
    # Coordinates Translation Functions
    ########################################
    @property
    def latitude(self):
        """Format Latitude Data Correctly"""
        if self.coord_format == 'dd':
            decimal_degrees = self._latitude[0] + (self._latitude[1] / 60)
            return [decimal_degrees, self._latitude[2]]
        elif self.coord_format == 'dms':
            minute_parts = modf(self._latitude[1])
            seconds = round(minute_parts[0] * 60)
            return [self._latitude[0], int(minute_parts[1]), seconds, self._latitude[2]]
        else:
            return self._latitude

    @property
    def longitude(self):
        """Format Longitude Data Correctly"""
        if self.coord_format == 'dd':
            decimal_degrees = self._longitude[0] + (self._longitude[1] / 60)
            return [decimal_degrees, self._longitude[2]]
        elif self.coord_format == 'dms':
            minute_parts = modf(self._longitude[1])
            seconds = round(minute_parts[0] * 60)
            return [self._longitude[0], int(minute_parts[1]), seconds, self._longitude[2]]
        else:
            return self._longitude

    ########################################
    # Logging Related Functions
    ########################################
    def start_logging(self, target_file, mode="append"):
        """
        Create GPS data log object
        """
        # Set Write Mode Overwrite or Append
        mode_code = 'w' if mode == 'new' else 'a'

        try:
            self.log_handle = open(target_file, mode_code)
        except AttributeError:
            print("Invalid FileName")
            return False

        self.log_en = True
        return True

    def stop_logging(self):
        """
        Closes the log file handler and disables further logging
        """
        try:
            self.log_handle.close()
        except AttributeError:
            print("Invalid Handle")
            return False

        self.log_en = False
        return True

    def write_log(self, log_string):
        """Attempts to write the last valid NMEA sentence character to the active file handler
        """
        try:
            self.log_handle.write(log_string)
        except TypeError:
            return False
        return True

    ########################################
    # Sentence Parsers
    ########################################
    def gprmc(self):
        """Parse Recommended Minimum Specific GPS/Transit data (RMC)Sentence.
        Updates UTC timestamp, latitude, longitude, Course, Speed, Date, and fix status
        """

        # UTC Timestamp
        try:
            utc_string = self.gps_segments[1]

            if utc_string:  # Possible timestamp found
                hours = (int(utc_string[0:2]) + self.local_offset) % 24
                minutes = int(utc_string[2:4])
                seconds = float(utc_string[4:])
                self.timestamp = [hours, minutes, seconds]
            else:  # No Time stamp yet
                self.timestamp = [0, 0, 0.0]

        except ValueError:  # Bad Timestamp value present
            return False

        # Date stamp
        try:
            date_string = self.gps_segments[9]

            # Date string printer function assumes to be year >=2000,
            # date_string() must be supplied with the correct century argument to display correctly
            if date_string:  # Possible date stamp found
                day = int(date_string[0:2])
                month = int(date_string[2:4])
                year = int(date_string[4:6])
                self.date = (day, month, year)
            else:  # No Date stamp yet
                self.date = (0, 0, 0)

        except ValueError:  # Bad Date stamp value present
            return False

        # Check Receiver Data Valid Flag
        if self.gps_segments[2] == 'A':  # Data from Receiver is Valid/Has Fix

            # Longitude / Latitude
            try:
                # Latitude
                l_string = self.gps_segments[3]
                lat_degs = int(l_string[0:2])
                lat_mins = float(l_string[2:])
                lat_hemi = self.gps_segments[4]

                # Longitude
                l_string = self.gps_segments[5]
                lon_degs = int(l_string[0:3])
                lon_mins = float(l_string[3:])
                lon_hemi = self.gps_segments[6]
            except ValueError:
                return False

            if lat_hemi not in self.__HEMISPHERES:
                return False

            if lon_hemi not in self.__HEMISPHERES:
                return False

            # Speed
            try:
                spd_knt = float(self.gps_segments[7])
            except ValueError:
                return False

            # Course
            try:
                if self.gps_segments[8]:
                    course = float(self.gps_segments[8])
                else:
                    course = 0.0
            except ValueError:
                return False

            # TODO - Add Magnetic Variation

            # Update Object Data
            self._latitude = [lat_degs, lat_mins, lat_hemi]
            self._longitude = [lon_degs, lon_mins, lon_hemi]
            # Include mph and hm/h
            self.speed = [spd_knt, spd_knt * 1.151, spd_knt * 1.852]
            self.course = course
            self.valid = True

            # Update Last Fix Time
            self.new_fix_time()

        else:  # Clear Position Data if Sentence is 'Invalid'
            self._latitude = [0, 0.0, 'N']
            self._longitude = [0, 0.0, 'W']
            self.speed = [0.0, 0.0, 0.0]
            self.course = 0.0
            self.valid = False

        return True

    def gpgll(self):
        """Parse Geographic Latitude and Longitude (GLL)Sentence. Updates UTC timestamp, latitude,
        longitude, and fix status"""

        # UTC Timestamp
        try:
            utc_string = self.gps_segments[5]

            if utc_string:  # Possible timestamp found
                hours = (int(utc_string[0:2]) + self.local_offset) % 24
                minutes = int(utc_string[2:4])
                seconds = float(utc_string[4:])
                self.timestamp = [hours, minutes, seconds]
            else:  # No Time stamp yet
                self.timestamp = [0, 0, 0.0]

        except ValueError:  # Bad Timestamp value present
            return False

        # Check Receiver Data Valid Flag
        if self.gps_segments[6] == 'A':  # Data from Receiver is Valid/Has Fix

            # Longitude / Latitude
            try:
                # Latitude
                l_string = self.gps_segments[1]
                lat_degs = int(l_string[0:2])
                lat_mins = float(l_string[2:])
                lat_hemi = self.gps_segments[2]

                # Longitude
                l_string = self.gps_segments[3]
                lon_degs = int(l_string[0:3])
                lon_mins = float(l_string[3:])
                lon_hemi = self.gps_segments[4]
            except ValueError:
                return False

            if lat_hemi not in self.__HEMISPHERES:
                return False

            if lon_hemi not in self.__HEMISPHERES:
                return False

            # Update Object Data
            self._latitude = [lat_degs, lat_mins, lat_hemi]
            self._longitude = [lon_degs, lon_mins, lon_hemi]
            self.valid = True

            # Update Last Fix Time
            self.new_fix_time()

        else:  # Clear Position Data if Sentence is 'Invalid'
            self._latitude = [0, 0.0, 'N']
            self._longitude = [0, 0.0, 'W']
            self.valid = False

        return True

    def gpvtg(self):
        """Parse Track Made Good and Ground Speed (VTG) Sentence. Updates speed and course"""
        try:
            course = float(self.gps_segments[1]) if self.gps_segments[1] else 0.0
            spd_knt = float(self.gps_segments[5]) if self.gps_segments[5] else 0.0
        except ValueError:
            return False

        # Include mph and km/h
        self.speed = (spd_knt, spd_knt * 1.151, spd_knt * 1.852)
        self.course = course
        return True

    def gpgga(self):
        """Parse Global Positioning System Fix Data (GGA) Sentence. Updates UTC timestamp, latitude, longitude,
        fix status, satellites in use, Horizontal Dilution of Precision (HDOP), altitude, geoid height and fix status"""

        try:
            # UTC Timestamp
            utc_string = self.gps_segments[1]

            # Skip timestamp if receiver doesn't have on yet
            if utc_string:
                hours = (int(utc_string[0:2]) + self.local_offset) % 24
                minutes = int(utc_string[2:4])
                seconds = float(utc_string[4:])
            else:
                hours = 0
                minutes = 0
                seconds = 0.0

            # Number of Satellites in Use
            satellites_in_use = int(self.gps_segments[7])

            # Get Fix Status
            fix_stat = int(self.gps_segments[6])

        except (ValueError, IndexError):
            return False

        try:
            # Horizontal Dilution of Precision
            hdop = float(self.gps_segments[8])
        except (ValueError, IndexError):
            hdop = 0.0

        # Process Location and Speed Data if Fix is GOOD
        if fix_stat:

            # Longitude / Latitude
            try:
                # Latitude
                l_string = self.gps_segments[2]
                lat_degs = int(l_string[0:2])
                lat_mins = float(l_string[2:])
                lat_hemi = self.gps_segments[3]

                # Longitude
                l_string = self.gps_segments[4]
                lon_degs = int(l_string[0:3])
                lon_mins = float(l_string[3:])
                lon_hemi = self.gps_segments[5]
            except ValueError:
                return False

            if lat_hemi not in self.__HEMISPHERES:
                return False

            if lon_hemi not in self.__HEMISPHERES:
                return False

            # Altitude / Height Above Geoid
            try:
                altitude = float(self.gps_segments[9])
                geoid_height = float(self.gps_segments[11])
            except ValueError:
                altitude = 0
                geoid_height = 0

            # Update Object Data
            self._latitude = [lat_degs, lat_mins, lat_hemi]
            self._longitude = [lon_degs, lon_mins, lon_hemi]
            self.altitude = altitude
            self.geoid_height = geoid_height

        # Update Object Data
        self.timestamp = [hours, minutes, seconds]
        self.satellites_in_use = satellites_in_use
        self.hdop = hdop
        self.fix_stat = fix_stat

        # If Fix is GOOD, update fix timestamp
        if fix_stat:
            self.new_fix_time()

        return True

    def gpgsa(self):
        """Parse GNSS DOP and Active Satellites (GSA) sentence. Updates GPS fix type, list of satellites used in
        fix calculation, Position Dilution of Precision (PDOP), Horizontal Dilution of Precision (HDOP), Vertical
        Dilution of Precision, and fix status"""

        # Fix Type (None,2D or 3D)
        try:
            fix_type = int(self.gps_segments[2])
        except ValueError:
            return False

        # Read All (up to 12) Available PRN Satellite Numbers
        sats_used = []
        for sats in range(12):
            sat_number_str = self.gps_segments[3 + sats]
            if sat_number_str:
                try:
                    sat_number = int(sat_number_str)
                    sats_used.append(sat_number)
                except ValueError:
                    return False
            else:
                break

        # PDOP,HDOP,VDOP
        try:
            pdop = float(self.gps_segments[15])
            hdop = float(self.gps_segments[16])
            vdop = float(self.gps_segments[17])
        except ValueError:
            return False

        # Update Object Data
        self.fix_type = fix_type

        # If Fix is GOOD, update fix timestamp
        if fix_type > self.__NO_FIX:
            self.new_fix_time()

        self.satellites_used = sats_used
        self.hdop = hdop
        self.vdop = vdop
        self.pdop = pdop

        return True

    def gpgsv(self):
        """Parse Satellites in View (GSV) sentence. Updates number of SV Sentences,the number of the last SV sentence
        parsed, and data on each satellite present in the sentence"""
        try:
            num_sv_sentences = int(self.gps_segments[1])
            current_sv_sentence = int(self.gps_segments[2])
            sats_in_view = int(self.gps_segments[3])
        except ValueError:
            return False

        # Create a blank dict to store all the satellite data from this sentence in:
        # satellite PRN is key, tuple containing telemetry is value
        satellite_dict = dict()

        # Calculate  Number of Satelites to pull data for and thus how many segment positions to read
        if num_sv_sentences == current_sv_sentence:
            # Last sentence may have 1-4 satellites; 5 - 20 positions
            sat_segment_limit = (sats_in_view - ((num_sv_sentences - 1) * 4)) * 5
        else:
            sat_segment_limit = 20  # Non-last sentences have 4 satellites and thus read up to position 20

        # Try to recover data for up to 4 satellites in sentence
        for sats in range(4, sat_segment_limit, 4):

            # If a PRN is present, grab satellite data
            if self.gps_segments[sats]:
                try:
                    sat_id = int(self.gps_segments[sats])
                except (ValueError,IndexError):
                    return False

                try:  # elevation can be null (no value) when not tracking
                    elevation = int(self.gps_segments[sats+1])
                except (ValueError,IndexError):
                    elevation = None

                try:  # azimuth can be null (no value) when not tracking
                    azimuth = int(self.gps_segments[sats+2])
                except (ValueError,IndexError):
                    azimuth = None

                try:  # SNR can be null (no value) when not tracking
                    snr = int(self.gps_segments[sats+3])
                except (ValueError,IndexError):
                    snr = None
            # If no PRN is found, then the sentence has no more satellites to read
            else:
                break

            # Add Satellite Data to Sentence Dict
            satellite_dict[sat_id] = (elevation, azimuth, snr)

        # Update Object Data
        self.total_sv_sentences = num_sv_sentences
        self.last_sv_sentence = current_sv_sentence
        self.satellites_in_view = sats_in_view

        # For a new set of sentences, we either clear out the existing sat data or
        # update it as additional SV sentences are parsed
        if current_sv_sentence == 1:
            self.satellite_data = satellite_dict
        else:
            self.satellite_data.update(satellite_dict)

        return True

    ##########################################
    # Data Stream Handler Functions
    ##########################################

    def new_sentence(self):
        """Adjust Object Flags in Preparation for a New Sentence"""
        self.gps_segments = ['']
        self.active_segment = 0
        self.crc_xor = 0
        self.sentence_active = True
        self.process_crc = True
        self.char_count = 0

    def update(self, new_char):
        """Process a new input char and updates GPS object if necessary based on special characters ('$', ',', '*')
        Function builds a list of received string that are validate by CRC prior to parsing by the  appropriate
        sentence function. Returns sentence type on successful parse, None otherwise"""

        valid_sentence = False

        # Validate new_char is a printable char
        ascii_char = ord(new_char)

        if 10 <= ascii_char <= 126:
            self.char_count += 1

            # Write Character to log file if enabled
            if self.log_en:
                self.write_log(new_char)

            # Check if a new string is starting ($)
            if new_char == '$':
                self.new_sentence()
                return None

            elif self.sentence_active:

                # Check if sentence is ending (*)
                if new_char == '*':
                    self.process_crc = False
                    self.active_segment += 1
                    self.gps_segments.append('')
                    return None

                # Check if a section is ended (,), Create a new substring to feed
                # characters to
                elif new_char == ',':
                    self.active_segment += 1
                    self.gps_segments.append('')

                # Store All Other printable character and check CRC when ready
                else:
                    self.gps_segments[self.active_segment] += new_char

                    # When CRC input is disabled, sentence is nearly complete
                    if not self.process_crc:

                        if len(self.gps_segments[self.active_segment]) == 2:
                            try:
                                final_crc = int(self.gps_segments[self.active_segment], 16)
                                if self.crc_xor == final_crc:
                                    valid_sentence = True
                                else:
                                    self.crc_fails += 1
                            except ValueError:
                                pass  # CRC Value was deformed and could not have been correct

                # Update CRC
                if self.process_crc:
                    self.crc_xor ^= ascii_char

                # If a Valid Sentence Was received and it's a supported sentence, then parse it!!
                if valid_sentence:
                    self.clean_sentences += 1  # Increment clean sentences received
                    self.sentence_active = False  # Clear Active Processing Flag

                    if self.gps_segments[0] in self.supported_sentences:

                        # parse the Sentence Based on the message type, return True if parse is clean
                        if self.supported_sentences[self.gps_segments[0]](self):

                            # Let host know that the GPS object was updated by returning parsed sentence type
                            self.parsed_sentences += 1
                            return self.gps_segments[0]

                # Check that the sentence buffer isn't filling up with Garage waiting for the sentence to complete
                if self.char_count > self.SENTENCE_LIMIT:
                    self.sentence_active = False

        # Tell Host no new sentence was parsed
        return None

    def new_fix_time(self):
        """Updates a high resolution counter with current time when fix is updated. Currently only triggered from
        GGA, GSA and RMC sentences"""
        try:
            self.fix_time = utime.ticks_ms()
        except NameError:
            self.fix_time = time.time()

    #########################################
    # User Helper Functions
    # These functions make working with the GPS object data easier
    #########################################

    def satellite_data_updated(self):
        """
        Checks if the all the GSV sentences in a group have been read, making satellite data complete
        :return: boolean
        """
        if self.total_sv_sentences > 0 and self.total_sv_sentences == self.last_sv_sentence:
            return True
        else:
            return False

    def unset_satellite_data_updated(self):
        """
        Mark GSV sentences as read indicating the data has been used and future updates are fresh
        """
        self.last_sv_sentence = 0

    def satellites_visible(self):
        """
        Returns a list of of the satellite PRNs currently visible to the receiver
        :return: list
        """
        return list(self.satellite_data.keys())

    def time_since_fix(self):
        """Returns number of millisecond since the last sentence with a valid fix was parsed. Returns 0 if
        no fix has been found"""

        # Test if a Fix has been found
        if self.fix_time == 0:
            return -1

        # Try calculating fix time using utime; if not running MicroPython
        # time.time() returns a floating point value in secs
        try:
            current = utime.ticks_diff(utime.ticks_ms(), self.fix_time)
        except NameError:
            current = (time.time() - self.fix_time) * 1000  # ms

        return current

    def compass_direction(self):
        """
        Determine a cardinal or inter-cardinal direction based on current course.
        :return: string
        """
        # Calculate the offset for a rotated compass
        if self.course >= 348.75:
            offset_course = 360 - self.course
        else:
            offset_course = self.course + 11.25

        # Each compass point is separated by 22.5 degrees, divide to find lookup value
        dir_index = floor(offset_course / 22.5)

        final_dir = self.__DIRECTIONS[dir_index]

        return final_dir

    def latitude_string(self):
        """
        Create a readable string of the current latitude data
        :return: string
        """
        if self.coord_format == 'dd':
            formatted_latitude = self.latitude
            lat_string = str(formatted_latitude[0]) + '° ' + str(self._latitude[2])
        elif self.coord_format == 'dms':
            formatted_latitude = self.latitude
            lat_string = str(formatted_latitude[0]) + '° ' + str(formatted_latitude[1]) + "' " + str(formatted_latitude[2]) + '" ' + str(formatted_latitude[3])
        else:
            lat_string = str(self._latitude[0]) + '° ' + str(self._latitude[1]) + "' " + str(self._latitude[2])
        return lat_string

    def longitude_string(self):
        """
        Create a readable string of the current longitude data
        :return: string
        """
        if self.coord_format == 'dd':
            formatted_longitude = self.longitude
            lon_string = str(formatted_longitude[0]) + '° ' + str(self._longitude[2])
        elif self.coord_format == 'dms':
            formatted_longitude = self.longitude
            lon_string = str(formatted_longitude[0]) + '° ' + str(formatted_longitude[1]) + "' " + str(formatted_longitude[2]) + '" ' + str(formatted_longitude[3])
        else:
            lon_string = str(self._longitude[0]) + '° ' + str(self._longitude[1]) + "' " + str(self._longitude[2])
        return lon_string

    def speed_string(self, unit='kph'):
        """
        Creates a readable string of the current speed data in one of three units
        :param unit: string of 'kph','mph, or 'knot'
        :return:
        """
        if unit == 'mph':
            speed_string = str(self.speed[1]) + ' mph'

        elif unit == 'knot':
            if self.speed[0] == 1:
                unit_str = ' knot'
            else:
                unit_str = ' knots'
            speed_string = str(self.speed[0]) + unit_str

        else:
            speed_string = str(self.speed[2]) + ' km/h'

        return speed_string

    def date_string(self, formatting='s_mdy', century='20'):
        """
        Creates a readable string of the current date.
        Can select between long format: Januray 1st, 2014
        or two short formats:
        11/01/2014 (MM/DD/YYYY)
        01/11/2014 (DD/MM/YYYY)
        :param formatting: string 's_mdy', 's_dmy', or 'long'
        :param century: int delineating the century the GPS data is from (19 for 19XX, 20 for 20XX)
        :return: date_string  string with long or short format date
        """

        # Long Format Januray 1st, 2014
        if formatting == 'long':
            # Retrieve Month string from private set
            month = self.__MONTHS[self.date[1] - 1]

            # Determine Date Suffix
            if self.date[0] in (1, 21, 31):
                suffix = 'st'
            elif self.date[0] in (2, 22):
                suffix = 'nd'
            elif self.date[0] == (3, 23):
                suffix = 'rd'
            else:
                suffix = 'th'

            day = str(self.date[0]) + suffix  # Create Day String

            year = century + str(self.date[2])  # Create Year String

            date_string = month + ' ' + day + ', ' + year  # Put it all together

        else:
            # Add leading zeros to day string if necessary
            if self.date[0] < 10:
                day = '0' + str(self.date[0])
            else:
                day = str(self.date[0])

            # Add leading zeros to month string if necessary
            if self.date[1] < 10:
                month = '0' + str(self.date[1])
            else:
                month = str(self.date[1])

            # Add leading zeros to year string if necessary
            if self.date[2] < 10:
                year = '0' + str(self.date[2])
            else:
                year = str(self.date[2])

            # Build final string based on desired formatting
            if formatting == 's_dmy':
                date_string = day + '/' + month + '/' + year

            else:  # Default date format
                date_string = month + '/' + day + '/' + year

        return date_string

    # All the currently supported NMEA sentences
    supported_sentences = {'GPRMC': gprmc, 'GLRMC': gprmc,
                           'GPGGA': gpgga, 'GLGGA': gpgga,
                           'GPVTG': gpvtg, 'GLVTG': gpvtg,
                           'GPGSA': gpgsa, 'GLGSA': gpgsa,
                           'GPGSV': gpgsv, 'GLGSV': gpgsv,
                           'GPGLL': gpgll, 'GLGLL': gpgll,
                           'GNGGA': gpgga, 'GNRMC': gprmc,
                           'GNVTG': gpvtg, 'GNGLL': gpgll,
                           'GNGSA': gpgsa,
                          }

if __name__ == "__main__":
    pass

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"""

# MicropyGPS - a GPS NMEA sentence parser for Micropython/Python 3.X

# The MIT License (MIT) - see LICENSE file

"""

# TODO:

# Time Since First Fix

# Distance/Time to Target

# More Helper Functions

# Dynamically limit sentences types to parse

from math import floor, modf

# Import utime or time for fix time handling

try:

# Assume running on MicroPython

import utime

except ImportError:

# Otherwise default to time module for non-embedded implementations

# Should still support millisecond resolution.

import time

class MicropyGPS(object):

"""GPS NMEA Sentence Parser. Creates object that stores all relevant GPS data and statistics.

Parses sentences one character at a time using update(). """

# Max Number of Characters a valid sentence can be (based on GGA sentence)

SENTENCE_LIMIT = 90

__HEMISPHERES = ('N', 'S', 'E', 'W')

__NO_FIX = 1

__FIX_2D = 2

__FIX_3D = 3

__DIRECTIONS = ('N', 'NNE', 'NE', 'ENE', 'E', 'ESE', 'SE', 'SSE', 'S', 'SSW', 'SW', 'WSW', 'W',

'WNW', 'NW', 'NNW')

__MONTHS = ('January', 'February', 'March', 'April', 'May',

'June', 'July', 'August', 'September', 'October',

'November', 'December')

def __init__(self, local_offset=0, location_formatting='ddm'):

"""

Setup GPS Object Status Flags, Internal Data Registers, etc

local_offset (int): Timzone Difference to UTC

location_formatting (str): Style For Presenting Longitude/Latitude:

Decimal Degree Minute (ddm) - 40° 26.767′ N

Degrees Minutes Seconds (dms) - 40° 26′ 46″ N

Decimal Degrees (dd) - 40.446° N

"""

#####################

# Object Status Flags

self.sentence_active = False

self.active_segment = 0

self.process_crc = False

self.gps_segments = []

self.crc_xor = 0

self.char_count = 0

self.fix_time = 0

#####################

# Sentence Statistics

self.crc_fails = 0

self.clean_sentences = 0

self.parsed_sentences = 0

#####################

# Logging Related

self.log_handle = None

self.log_en = False

#####################

# Data From Sentences

# Time

self.timestamp = [0, 0, 0.0]

self.date = [0, 0, 0]

self.local_offset = local_offset

# Position/Motion

self._latitude = [0, 0.0, 'N']

self._longitude = [0, 0.0, 'W']

self.coord_format = location_formatting

self.speed = [0.0, 0.0, 0.0]

self.course = 0.0

self.altitude = 0.0

self.geoid_height = 0.0

# GPS Info

self.satellites_in_view = 0

self.satellites_in_use = 0

self.satellites_used = []

self.last_sv_sentence = 0

self.total_sv_sentences = 0

self.satellite_data = dict()

self.hdop = 0.0

self.pdop = 0.0

self.vdop = 0.0

self.valid = False

self.fix_stat = 0

self.fix_type = 1

########################################

# Coordinates Translation Functions

########################################

@property

def latitude(self):

"""Format Latitude Data Correctly"""

if self.coord_format == 'dd':

decimal_degrees = self._latitude[0] + (self._latitude[1] / 60)

return [decimal_degrees, self._latitude[2]]

elif self.coord_format == 'dms':

minute_parts = modf(self._latitude[1])

seconds = round(minute_parts[0] * 60)

return [self._latitude[0], int(minute_parts[1]), seconds, self._latitude[2]]

else:

return self._latitude

@property

def longitude(self):

"""Format Longitude Data Correctly"""

if self.coord_format == 'dd':

decimal_degrees = self._longitude[0] + (self._longitude[1] / 60)

return [decimal_degrees, self._longitude[2]]

elif self.coord_format == 'dms':

minute_parts = modf(self._longitude[1])

seconds = round(minute_parts[0] * 60)

return [self._longitude[0], int(minute_parts[1]), seconds, self._longitude[2]]

else:

return self._longitude

########################################

# Logging Related Functions

########################################

def start_logging(self, target_file, mode="append"):

"""

Create GPS data log object

"""

# Set Write Mode Overwrite or Append

mode_code = 'w' if mode == 'new' else 'a'

try:

self.log_handle = open(target_file, mode_code)

except AttributeError:

print("Invalid FileName")

return False

self.log_en = True

return True

def stop_logging(self):

"""

Closes the log file handler and disables further logging

"""

try:

self.log_handle.close()

except AttributeError:

print("Invalid Handle")

return False

self.log_en = False

return True

def write_log(self, log_string):

"""Attempts to write the last valid NMEA sentence character to the active file handler

"""

try:

self.log_handle.write(log_string)

except TypeError:

return False

return True

########################################

# Sentence Parsers

########################################

def gprmc(self):

"""Parse Recommended Minimum Specific GPS/Transit data (RMC)Sentence.

Updates UTC timestamp, latitude, longitude, Course, Speed, Date, and fix status

"""

# UTC Timestamp

try:

utc_string = self.gps_segments[1]

if utc_string: # Possible timestamp found

hours = (int(utc_string[0:2]) + self.local_offset) % 24

minutes = int(utc_string[2:4])

seconds = float(utc_string[4:])

self.timestamp = [hours, minutes, seconds]

else: # No Time stamp yet

self.timestamp = [0, 0, 0.0]

except ValueError: # Bad Timestamp value present

return False

# Date stamp

try:

date_string = self.gps_segments[9]

# Date string printer function assumes to be year >=2000,

# date_string() must be supplied with the correct century argument to display correctly

if date_string: # Possible date stamp found

day = int(date_string[0:2])

month = int(date_string[2:4])

year = int(date_string[4:6])

self.date = (day, month, year)

else: # No Date stamp yet

self.date = (0, 0, 0)

except ValueError: # Bad Date stamp value present

return False

# Check Receiver Data Valid Flag

if self.gps_segments[2] == 'A': # Data from Receiver is Valid/Has Fix

# Longitude / Latitude

try:

# Latitude

l_string = self.gps_segments[3]

lat_degs = int(l_string[0:2])

lat_mins = float(l_string[2:])

lat_hemi = self.gps_segments[4]

# Longitude

l_string = self.gps_segments[5]

lon_degs = int(l_string[0:3])

lon_mins = float(l_string[3:])

lon_hemi = self.gps_segments[6]

except ValueError:

return False

if lat_hemi not in self.__HEMISPHERES:

return False

if lon_hemi not in self.__HEMISPHERES:

return False

# Speed

try:

spd_knt = float(self.gps_segments[7])

except ValueError:

return False

# Course

try:

if self.gps_segments[8]:

course = float(self.gps_segments[8])

else:

course = 0.0

except ValueError:

return False

# TODO - Add Magnetic Variation

# Update Object Data

self._latitude = [lat_degs, lat_mins, lat_hemi]

self._longitude = [lon_degs, lon_mins, lon_hemi]

# Include mph and hm/h

self.speed = [spd_knt, spd_knt * 1.151, spd_knt * 1.852]

self.course = course

self.valid = True

# Update Last Fix Time

self.new_fix_time()

else: # Clear Position Data if Sentence is 'Invalid'

self._latitude = [0, 0.0, 'N']

self._longitude = [0, 0.0, 'W']

self.speed = [0.0, 0.0, 0.0]

self.course = 0.0

self.valid = False

return True

def gpgll(self):

"""Parse Geographic Latitude and Longitude (GLL)Sentence. Updates UTC timestamp, latitude,

longitude, and fix status"""

# UTC Timestamp

try:

utc_string = self.gps_segments[5]

if utc_string: # Possible timestamp found

hours = (int(utc_string[0:2]) + self.local_offset) % 24

minutes = int(utc_string[2:4])

seconds = float(utc_string[4:])

self.timestamp = [hours, minutes, seconds]

else: # No Time stamp yet

self.timestamp = [0, 0, 0.0]

except ValueError: # Bad Timestamp value present

return False

# Check Receiver Data Valid Flag

if self.gps_segments[6] == 'A': # Data from Receiver is Valid/Has Fix

# Longitude / Latitude

try:

# Latitude

l_string = self.gps_segments[1]

lat_degs = int(l_string[0:2])

lat_mins = float(l_string[2:])

lat_hemi = self.gps_segments[2]

# Longitude

l_string = self.gps_segments[3]

lon_degs = int(l_string[0:3])

lon_mins = float(l_string[3:])

lon_hemi = self.gps_segments[4]

except ValueError:

return False

if lat_hemi not in self.__HEMISPHERES:

return False

if lon_hemi not in self.__HEMISPHERES:

return False

# Update Object Data

self._latitude = [lat_degs, lat_mins, lat_hemi]

self._longitude = [lon_degs, lon_mins, lon_hemi]

self.valid = True

# Update Last Fix Time

self.new_fix_time()

else: # Clear Position Data if Sentence is 'Invalid'

self._latitude = [0, 0.0, 'N']

self._longitude = [0, 0.0, 'W']

self.valid = False

return True

def gpvtg(self):

"""Parse Track Made Good and Ground Speed (VTG) Sentence. Updates speed and course"""

try:

course = float(self.gps_segments[1]) if self.gps_segments[1] else 0.0

spd_knt = float(self.gps_segments[5]) if self.gps_segments[5] else 0.0

except ValueError:

return False

# Include mph and km/h

self.speed = (spd_knt, spd_knt * 1.151, spd_knt * 1.852)

self.course = course

return True

def gpgga(self):

"""Parse Global Positioning System Fix Data (GGA) Sentence. Updates UTC timestamp, latitude, longitude,

fix status, satellites in use, Horizontal Dilution of Precision (HDOP), altitude, geoid height and fix status"""

try:

# UTC Timestamp

utc_string = self.gps_segments[1]

# Skip timestamp if receiver doesn't have on yet

if utc_string:

hours = (int(utc_string[0:2]) + self.local_offset) % 24

minutes = int(utc_string[2:4])

seconds = float(utc_string[4:])

else:

hours = 0

minutes = 0

seconds = 0.0

# Number of Satellites in Use

satellites_in_use = int(self.gps_segments[7])

# Get Fix Status

fix_stat = int(self.gps_segments[6])

except (ValueError, IndexError):

return False

try:

# Horizontal Dilution of Precision

hdop = float(self.gps_segments[8])

except (ValueError, IndexError):

hdop = 0.0

# Process Location and Speed Data if Fix is GOOD

if fix_stat:

# Longitude / Latitude

try:

# Latitude

l_string = self.gps_segments[2]

lat_degs = int(l_string[0:2])

lat_mins = float(l_string[2:])

lat_hemi = self.gps_segments[3]

# Longitude

l_string = self.gps_segments[4]

lon_degs = int(l_string[0:3])

lon_mins = float(l_string[3:])

lon_hemi = self.gps_segments[5]

except ValueError:

return False

if lat_hemi not in self.__HEMISPHERES:

return False

if lon_hemi not in self.__HEMISPHERES:

return False

# Altitude / Height Above Geoid

try:

altitude = float(self.gps_segments[9])

geoid_height = float(self.gps_segments[11])

except ValueError:

altitude = 0

geoid_height = 0

# Update Object Data

self._latitude = [lat_degs, lat_mins, lat_hemi]

self._longitude = [lon_degs, lon_mins, lon_hemi]

self.altitude = altitude

self.geoid_height = geoid_height

# Update Object Data

self.timestamp = [hours, minutes, seconds]

self.satellites_in_use = satellites_in_use

self.hdop = hdop

self.fix_stat = fix_stat

# If Fix is GOOD, update fix timestamp

if fix_stat:

self.new_fix_time()

return True

def gpgsa(self):

"""Parse GNSS DOP and Active Satellites (GSA) sentence. Updates GPS fix type, list of satellites used in

fix calculation, Position Dilution of Precision (PDOP), Horizontal Dilution of Precision (HDOP), Vertical

Dilution of Precision, and fix status"""

# Fix Type (None,2D or 3D)

try:

fix_type = int(self.gps_segments[2])

except ValueError:

return False

# Read All (up to 12) Available PRN Satellite Numbers

sats_used = []

for sats in range(12):

sat_number_str = self.gps_segments[3 + sats]

if sat_number_str:

try:

sat_number = int(sat_number_str)

sats_used.append(sat_number)

except ValueError:

return False

else:

break

# PDOP,HDOP,VDOP

try:

pdop = float(self.gps_segments[15])

hdop = float(self.gps_segments[16])

vdop = float(self.gps_segments[17])

except ValueError:

return False

# Update Object Data

self.fix_type = fix_type

# If Fix is GOOD, update fix timestamp

if fix_type > self.__NO_FIX:

self.new_fix_time()

self.satellites_used = sats_used

self.hdop = hdop

self.vdop = vdop

self.pdop = pdop

return True

def gpgsv(self):

"""Parse Satellites in View (GSV) sentence. Updates number of SV Sentences,the number of the last SV sentence

parsed, and data on each satellite present in the sentence"""

try:

num_sv_sentences = int(self.gps_segments[1])

current_sv_sentence = int(self.gps_segments[2])

sats_in_view = int(self.gps_segments[3])

except ValueError:

return False

# Create a blank dict to store all the satellite data from this sentence in:

# satellite PRN is key, tuple containing telemetry is value

satellite_dict = dict()

# Calculate Number of Satelites to pull data for and thus how many segment positions to read

if num_sv_sentences == current_sv_sentence:

# Last sentence may have 1-4 satellites; 5 - 20 positions

sat_segment_limit = (sats_in_view - ((num_sv_sentences - 1) * 4)) * 5

else:

sat_segment_limit = 20 # Non-last sentences have 4 satellites and thus read up to position 20

# Try to recover data for up to 4 satellites in sentence

for sats in range(4, sat_segment_limit, 4):

# If a PRN is present, grab satellite data

if self.gps_segments[sats]:

try:

sat_id = int(self.gps_segments[sats])

except (ValueError,IndexError):

return False

try: # elevation can be null (no value) when not tracking

elevation = int(self.gps_segments[sats+1])

except (ValueError,IndexError):

elevation = None

try: # azimuth can be null (no value) when not tracking

azimuth = int(self.gps_segments[sats+2])

except (ValueError,IndexError):

azimuth = None

try: # SNR can be null (no value) when not tracking

snr = int(self.gps_segments[sats+3])

except (ValueError,IndexError):

snr = None

# If no PRN is found, then the sentence has no more satellites to read

else:

break

# Add Satellite Data to Sentence Dict

satellite_dict[sat_id] = (elevation, azimuth, snr)

# Update Object Data

self.total_sv_sentences = num_sv_sentences

self.last_sv_sentence = current_sv_sentence

self.satellites_in_view = sats_in_view

# For a new set of sentences, we either clear out the existing sat data or

# update it as additional SV sentences are parsed

if current_sv_sentence == 1:

self.satellite_data = satellite_dict

else:

self.satellite_data.update(satellite_dict)

return True

##########################################

# Data Stream Handler Functions

##########################################

def new_sentence(self):

"""Adjust Object Flags in Preparation for a New Sentence"""

self.gps_segments = ['']

self.active_segment = 0

self.crc_xor = 0

self.sentence_active = True

self.process_crc = True

self.char_count = 0

def update(self, new_char):

"""Process a new input char and updates GPS object if necessary based on special characters ('$', ',', '*')

Function builds a list of received string that are validate by CRC prior to parsing by the appropriate

sentence function. Returns sentence type on successful parse, None otherwise"""

valid_sentence = False

# Validate new_char is a printable char

ascii_char = ord(new_char)

if 10 <= ascii_char <= 126:

self.char_count += 1

# Write Character to log file if enabled

if self.log_en:

self.write_log(new_char)

# Check if a new string is starting ($)

if new_char == '$':

self.new_sentence()

return None

elif self.sentence_active:

# Check if sentence is ending (*)

if new_char == '*':

self.process_crc = False

self.active_segment += 1

self.gps_segments.append('')

return None

# Check if a section is ended (,), Create a new substring to feed

# characters to

elif new_char == ',':

self.active_segment += 1

self.gps_segments.append('')

# Store All Other printable character and check CRC when ready

else:

self.gps_segments[self.active_segment] += new_char

# When CRC input is disabled, sentence is nearly complete

if not self.process_crc:

if len(self.gps_segments[self.active_segment]) == 2:

try:

final_crc = int(self.gps_segments[self.active_segment], 16)

if self.crc_xor == final_crc:

valid_sentence = True

else:

self.crc_fails += 1

except ValueError:

pass # CRC Value was deformed and could not have been correct

# Update CRC

if self.process_crc:

self.crc_xor ^= ascii_char

# If a Valid Sentence Was received and it's a supported sentence, then parse it!!

if valid_sentence:

self.clean_sentences += 1 # Increment clean sentences received

self.sentence_active = False # Clear Active Processing Flag

if self.gps_segments[0] in self.supported_sentences:

# parse the Sentence Based on the message type, return True if parse is clean

if self.supported_sentences[self.gps_segments[0]](self):

# Let host know that the GPS object was updated by returning parsed sentence type

self.parsed_sentences += 1

return self.gps_segments[0]

# Check that the sentence buffer isn't filling up with Garage waiting for the sentence to complete

if self.char_count > self.SENTENCE_LIMIT:

self.sentence_active = False

# Tell Host no new sentence was parsed

return None

def new_fix_time(self):

"""Updates a high resolution counter with current time when fix is updated. Currently only triggered from

GGA, GSA and RMC sentences"""

try:

self.fix_time = utime.ticks_ms()

except NameError:

self.fix_time = time.time()

#########################################

# User Helper Functions

# These functions make working with the GPS object data easier

#########################################

def satellite_data_updated(self):

"""

Checks if the all the GSV sentences in a group have been read, making satellite data complete

:return: boolean

"""

if self.total_sv_sentences > 0 and self.total_sv_sentences == self.last_sv_sentence:

return True

else:

return False

def unset_satellite_data_updated(self):

"""

Mark GSV sentences as read indicating the data has been used and future updates are fresh

"""

self.last_sv_sentence = 0

def satellites_visible(self):

"""

Returns a list of of the satellite PRNs currently visible to the receiver

:return: list

"""

return list(self.satellite_data.keys())

def time_since_fix(self):

"""Returns number of millisecond since the last sentence with a valid fix was parsed. Returns 0 if

no fix has been found"""

# Test if a Fix has been found

if self.fix_time == 0:

return -1

# Try calculating fix time using utime; if not running MicroPython

# time.time() returns a floating point value in secs

try:

current = utime.ticks_diff(utime.ticks_ms(), self.fix_time)

except NameError:

current = (time.time() - self.fix_time) * 1000 # ms

return current

def compass_direction(self):

"""

Determine a cardinal or inter-cardinal direction based on current course.

:return: string

"""

# Calculate the offset for a rotated compass

if self.course >= 348.75:

offset_course = 360 - self.course

else:

offset_course = self.course + 11.25

# Each compass point is separated by 22.5 degrees, divide to find lookup value

dir_index = floor(offset_course / 22.5)

final_dir = self.__DIRECTIONS[dir_index]

return final_dir

def latitude_string(self):

"""

Create a readable string of the current latitude data

:return: string

"""

if self.coord_format == 'dd':

formatted_latitude = self.latitude

lat_string = str(formatted_latitude[0]) + '° ' + str(self._latitude[2])

elif self.coord_format == 'dms':

formatted_latitude = self.latitude

lat_string = str(formatted_latitude[0]) + '° ' + str(formatted_latitude[1]) + "' " + str(formatted_latitude[2]) + '" ' + str(formatted_latitude[3])

else:

lat_string = str(self._latitude[0]) + '° ' + str(self._latitude[1]) + "' " + str(self._latitude[2])

return lat_string

def longitude_string(self):

"""

Create a readable string of the current longitude data

:return: string

"""

if self.coord_format == 'dd':

formatted_longitude = self.longitude

lon_string = str(formatted_longitude[0]) + '° ' + str(self._longitude[2])

elif self.coord_format == 'dms':

formatted_longitude = self.longitude

lon_string = str(formatted_longitude[0]) + '° ' + str(formatted_longitude[1]) + "' " + str(formatted_longitude[2]) + '" ' + str(formatted_longitude[3])

else:

lon_string = str(self._longitude[0]) + '° ' + str(self._longitude[1]) + "' " + str(self._longitude[2])

return lon_string

def speed_string(self, unit='kph'):

"""

Creates a readable string of the current speed data in one of three units

:param unit: string of 'kph','mph, or 'knot'

:return:

"""

if unit == 'mph':

speed_string = str(self.speed[1]) + ' mph'

elif unit == 'knot':

if self.speed[0] == 1:

unit_str = ' knot'

else:

unit_str = ' knots'

speed_string = str(self.speed[0]) + unit_str

else:

speed_string = str(self.speed[2]) + ' km/h'

return speed_string

def date_string(self, formatting='s_mdy', century='20'):

"""

Creates a readable string of the current date.

Can select between long format: Januray 1st, 2014

or two short formats:

11/01/2014 (MM/DD/YYYY)

01/11/2014 (DD/MM/YYYY)

:param formatting: string 's_mdy', 's_dmy', or 'long'

:param century: int delineating the century the GPS data is from (19 for 19XX, 20 for 20XX)

:return: date_string string with long or short format date

"""

# Long Format Januray 1st, 2014

if formatting == 'long':

# Retrieve Month string from private set

month = self.__MONTHS[self.date[1] - 1]

# Determine Date Suffix

if self.date[0] in (1, 21, 31):

suffix = 'st'

elif self.date[0] in (2, 22):

suffix = 'nd'

elif self.date[0] == (3, 23):

suffix = 'rd'

else:

suffix = 'th'

day = str(self.date[0]) + suffix # Create Day String

year = century + str(self.date[2]) # Create Year String

date_string = month + ' ' + day + ', ' + year # Put it all together

else:

# Add leading zeros to day string if necessary

if self.date[0] < 10:

day = '0' + str(self.date[0])

else:

day = str(self.date[0])

# Add leading zeros to month string if necessary

if self.date[1] < 10:

month = '0' + str(self.date[1])

else:

month = str(self.date[1])

# Add leading zeros to year string if necessary

if self.date[2] < 10:

year = '0' + str(self.date[2])

else:

year = str(self.date[2])

# Build final string based on desired formatting

if formatting == 's_dmy':

date_string = day + '/' + month + '/' + year

else: # Default date format

date_string = month + '/' + day + '/' + year

return date_string

# All the currently supported NMEA sentences

supported_sentences = {'GPRMC': gprmc, 'GLRMC': gprmc,

'GPGGA': gpgga, 'GLGGA': gpgga,

'GPVTG': gpvtg, 'GLVTG': gpvtg,

'GPGSA': gpgsa, 'GLGSA': gpgsa,

'GPGSV': gpgsv, 'GLGSV': gpgsv,

'GPGLL': gpgll, 'GLGLL': gpgll,

'GNGGA': gpgga, 'GNRMC': gprmc,

'GNVTG': gpvtg, 'GNGLL': gpgll,

'GNGSA': gpgsa,

}

if __name__ == "__main__":

pass

ssd1306.py

The second part is the library for the OLED display, which handles the communication and display functionalities of the 0.96″ OLED screen.

# MicroPython SSD1306 OLED driver, I2C and SPI interfaces

from micropython import const
import framebuf


# register definitions
SET_CONTRAST = const(0x81)
SET_ENTIRE_ON = const(0xA4)
SET_NORM_INV = const(0xA6)
SET_DISP = const(0xAE)
SET_MEM_ADDR = const(0x20)
SET_COL_ADDR = const(0x21)
SET_PAGE_ADDR = const(0x22)
SET_DISP_START_LINE = const(0x40)
SET_SEG_REMAP = const(0xA0)
SET_MUX_RATIO = const(0xA8)
SET_COM_OUT_DIR = const(0xC0)
SET_DISP_OFFSET = const(0xD3)
SET_COM_PIN_CFG = const(0xDA)
SET_DISP_CLK_DIV = const(0xD5)
SET_PRECHARGE = const(0xD9)
SET_VCOM_DESEL = const(0xDB)
SET_CHARGE_PUMP = const(0x8D)

# Subclassing FrameBuffer provides support for graphics primitives
# http://docs.micropython.org/en/latest/pyboard/library/framebuf.html
class SSD1306(framebuf.FrameBuffer):
    def __init__(self, width, height, external_vcc):
        self.width = width
        self.height = height
        self.external_vcc = external_vcc
        self.pages = self.height // 8
        self.buffer = bytearray(self.pages * self.width)
        super().__init__(self.buffer, self.width, self.height, framebuf.MONO_VLSB)
        self.init_display()

    def init_display(self):
        for cmd in (
            SET_DISP | 0x00,  # off
            # address setting
            SET_MEM_ADDR,
            0x00,  # horizontal
            # resolution and layout
            SET_DISP_START_LINE | 0x00,
            SET_SEG_REMAP | 0x01,  # column addr 127 mapped to SEG0
            SET_MUX_RATIO,
            self.height - 1,
            SET_COM_OUT_DIR | 0x08,  # scan from COM[N] to COM0
            SET_DISP_OFFSET,
            0x00,
            SET_COM_PIN_CFG,
            0x02 if self.width > 2 * self.height else 0x12,
            # timing and driving scheme
            SET_DISP_CLK_DIV,
            0x80,
            SET_PRECHARGE,
            0x22 if self.external_vcc else 0xF1,
            SET_VCOM_DESEL,
            0x30,  # 0.83*Vcc
            # display
            SET_CONTRAST,
            0xFF,  # maximum
            SET_ENTIRE_ON,  # output follows RAM contents
            SET_NORM_INV,  # not inverted
            # charge pump
            SET_CHARGE_PUMP,
            0x10 if self.external_vcc else 0x14,
            SET_DISP | 0x01,
        ):  # on
            self.write_cmd(cmd)
        self.fill(0)
        self.show()

    def poweroff(self):
        self.write_cmd(SET_DISP | 0x00)

    def poweron(self):
        self.write_cmd(SET_DISP | 0x01)

    def contrast(self, contrast):
        self.write_cmd(SET_CONTRAST)
        self.write_cmd(contrast)

    def invert(self, invert):
        self.write_cmd(SET_NORM_INV | (invert & 1))

    def show(self):
        x0 = 0
        x1 = self.width - 1
        if self.width == 64:
            # displays with width of 64 pixels are shifted by 32
            x0 += 32
            x1 += 32
        self.write_cmd(SET_COL_ADDR)
        self.write_cmd(x0)
        self.write_cmd(x1)
        self.write_cmd(SET_PAGE_ADDR)
        self.write_cmd(0)
        self.write_cmd(self.pages - 1)
        self.write_data(self.buffer)


class SSD1306_I2C(SSD1306):
    def __init__(self, width, height, i2c, addr=0x3C, external_vcc=False):
        self.i2c = i2c
        self.addr = addr
        self.temp = bytearray(2)
        self.write_list = [b"\x40", None]  # Co=0, D/C#=1
        super().__init__(width, height, external_vcc)

    def write_cmd(self, cmd):
        self.temp[0] = 0x80  # Co=1, D/C#=0
        self.temp[1] = cmd
        self.i2c.writeto(self.addr, self.temp)

    def write_data(self, buf):
        self.write_list[1] = buf
        self.i2c.writevto(self.addr, self.write_list)


class SSD1306_SPI(SSD1306):
    def __init__(self, width, height, spi, dc, res, cs, external_vcc=False):
        self.rate = 10 * 1024 * 1024
        dc.init(dc.OUT, value=0)
        res.init(res.OUT, value=0)
        cs.init(cs.OUT, value=1)
        self.spi = spi
        self.dc = dc
        self.res = res
        self.cs = cs
        import time

        self.res(1)
        time.sleep_ms(1)
        self.res(0)
        time.sleep_ms(10)
        self.res(1)
        super().__init__(width, height, external_vcc)

    def write_cmd(self, cmd):
        self.spi.init(baudrate=self.rate, polarity=0, phase=0)
        self.cs(1)
        self.dc(0)
        self.cs(0)
        self.spi.write(bytearray([cmd]))
        self.cs(1)

    def write_data(self, buf):
        self.spi.init(baudrate=self.rate, polarity=0, phase=0)
        self.cs(1)
        self.dc(1)
        self.cs(0)
        self.spi.write(buf)
        self.cs(1)

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# MicroPython SSD1306 OLED driver, I2C and SPI interfaces

from micropython import const

import framebuf

# register definitions

SET_CONTRAST = const(0x81)

SET_ENTIRE_ON = const(0xA4)

SET_NORM_INV = const(0xA6)

SET_DISP = const(0xAE)

SET_MEM_ADDR = const(0x20)

SET_COL_ADDR = const(0x21)

SET_PAGE_ADDR = const(0x22)

SET_DISP_START_LINE = const(0x40)

SET_SEG_REMAP = const(0xA0)

SET_MUX_RATIO = const(0xA8)

SET_COM_OUT_DIR = const(0xC0)

SET_DISP_OFFSET = const(0xD3)

SET_COM_PIN_CFG = const(0xDA)

SET_DISP_CLK_DIV = const(0xD5)

SET_PRECHARGE = const(0xD9)

SET_VCOM_DESEL = const(0xDB)

SET_CHARGE_PUMP = const(0x8D)

# Subclassing FrameBuffer provides support for graphics primitives

# http://docs.micropython.org/en/latest/pyboard/library/framebuf.html

class SSD1306(framebuf.FrameBuffer):

def __init__(self, width, height, external_vcc):

self.width = width

self.height = height

self.external_vcc = external_vcc

self.pages = self.height // 8

self.buffer = bytearray(self.pages * self.width)

super().__init__(self.buffer, self.width, self.height, framebuf.MONO_VLSB)

self.init_display()

def init_display(self):

for cmd in (

SET_DISP | 0x00, # off

# address setting

SET_MEM_ADDR,

0x00, # horizontal

# resolution and layout

SET_DISP_START_LINE | 0x00,

SET_SEG_REMAP | 0x01, # column addr 127 mapped to SEG0

SET_MUX_RATIO,

self.height - 1,

SET_COM_OUT_DIR | 0x08, # scan from COM[N] to COM0

SET_DISP_OFFSET,

0x00,

SET_COM_PIN_CFG,

0x02 if self.width > 2 * self.height else 0x12,

# timing and driving scheme

SET_DISP_CLK_DIV,

0x80,

SET_PRECHARGE,

0x22 if self.external_vcc else 0xF1,

SET_VCOM_DESEL,

0x30, # 0.83*Vcc

# display

SET_CONTRAST,

0xFF, # maximum

SET_ENTIRE_ON, # output follows RAM contents

SET_NORM_INV, # not inverted

# charge pump

SET_CHARGE_PUMP,

0x10 if self.external_vcc else 0x14,

SET_DISP | 0x01,

): # on

self.write_cmd(cmd)

self.fill(0)

self.show()

def poweroff(self):

self.write_cmd(SET_DISP | 0x00)

def poweron(self):

self.write_cmd(SET_DISP | 0x01)

def contrast(self, contrast):

self.write_cmd(SET_CONTRAST)

self.write_cmd(contrast)

def invert(self, invert):

self.write_cmd(SET_NORM_INV | (invert & 1))

def show(self):

x0 = 0

x1 = self.width - 1

if self.width == 64:

# displays with width of 64 pixels are shifted by 32

x0 += 32

x1 += 32

self.write_cmd(SET_COL_ADDR)

self.write_cmd(x0)

self.write_cmd(x1)

self.write_cmd(SET_PAGE_ADDR)

self.write_cmd(0)

self.write_cmd(self.pages - 1)

self.write_data(self.buffer)

class SSD1306_I2C(SSD1306):

def __init__(self, width, height, i2c, addr=0x3C, external_vcc=False):

self.i2c = i2c

self.addr = addr

self.temp = bytearray(2)

self.write_list = [b"\x40", None] # Co=0, D/C#=1

super().__init__(width, height, external_vcc)

def write_cmd(self, cmd):

self.temp[0] = 0x80 # Co=1, D/C#=0

self.temp[1] = cmd

self.i2c.writeto(self.addr, self.temp)

def write_data(self, buf):

self.write_list[1] = buf

self.i2c.writevto(self.addr, self.write_list)

class SSD1306_SPI(SSD1306):

def __init__(self, width, height, spi, dc, res, cs, external_vcc=False):

self.rate = 10 * 1024 * 1024

dc.init(dc.OUT, value=0)

res.init(res.OUT, value=0)

cs.init(cs.OUT, value=1)

self.spi = spi

self.dc = dc

self.res = res

self.cs = cs

import time

self.res(1)

time.sleep_ms(1)

self.res(0)

time.sleep_ms(10)

self.res(1)

super().__init__(width, height, external_vcc)

def write_cmd(self, cmd):

self.spi.init(baudrate=self.rate, polarity=0, phase=0)

self.cs(1)

self.dc(0)

self.cs(0)

self.spi.write(bytearray([cmd]))

self.cs(1)

def write_data(self, buf):

self.spi.init(baudrate=self.rate, polarity=0, phase=0)

self.cs(1)

self.dc(1)

self.cs(0)

self.spi.write(buf)

self.cs(1)

main.py

from machine import Pin, UART, I2C
import utime
from ssd1306 import SSD1306_I2C
from micropyGPS import MicropyGPS

# Initialize I2C and OLED display
i2c = I2C(1, sda=Pin(14), scl=Pin(15), freq=400000)
oled = SSD1306_I2C(128, 64, i2c)

# Initialize GPS module
gps_module = UART(1, baudrate=9600, tx=Pin(4), rx=Pin(5))
time_zone = -3
gps = MicropyGPS(time_zone)

def convert_coordinates(sections):
    if sections[0] == 0:  # sections[0] contains the degrees
        return None

    # sections[1] contains the minutes
    data = sections[0] + (sections[1] / 60.0)

    # sections[2] contains 'E', 'W', 'N', 'S'
    if sections[2] == 'S':
        data = -data
    if sections[2] == 'W':
        data = -data

    data = '{0:.6f}'.format(data)  # 6 decimal places
    return str(data)


while True:
    length = gps_module.any()
    if length > 0:
        data = gps_module.read(length)
        for byte in data:
            message = gps.update(chr(byte))

    latitude = convert_coordinates(gps.latitude)
    longitude = convert_coordinates(gps.longitude)

    if latitude is None or longitude is None:
        oled.fill(0)
        oled.text("Data unavailable", 35, 25)
        oled.text("No coordinates", 22, 40)
        oled.show()
        continue

    
    oled.fill(0)
    oled.text('Satellites: ' + str(gps.satellites_in_use), 10, 0)
    oled.text('Lat: ' + latitude, 0, 18)
    print('Lat: ' + latitude)
    oled.text('Lon: ' + longitude, 0, 36)
    print('Lon: ' + longitude)

    oled.show()

from machine import Pin, UART, I2C

import utime

from ssd1306 import SSD1306_I2C

from micropyGPS import MicropyGPS

# Initialize I2C and OLED display

i2c = I2C(1, sda=Pin(14), scl=Pin(15), freq=400000)

oled = SSD1306_I2C(128, 64, i2c)

# Initialize GPS module

gps_module = UART(1, baudrate=9600, tx=Pin(4), rx=Pin(5))

time_zone = -3

gps = MicropyGPS(time_zone)

def convert_coordinates(sections):

if sections[0] == 0: # sections[0] contains the degrees

return None

# sections[1] contains the minutes

data = sections[0] + (sections[1] / 60.0)

# sections[2] contains 'E', 'W', 'N', 'S'

if sections[2] == 'S':

data = -data

if sections[2] == 'W':

data = -data

data = '{0:.6f}'.format(data) # 6 decimal places

return str(data)

while True:

length = gps_module.any()

if length > 0:

data = gps_module.read(length)

for byte in data:

message = gps.update(chr(byte))

latitude = convert_coordinates(gps.latitude)

longitude = convert_coordinates(gps.longitude)

if latitude is None or longitude is None:

oled.fill(0)

oled.text("Data unavailable", 35, 25)

oled.text("No coordinates", 22, 40)

oled.show()

continue

oled.fill(0)

oled.text('Satellites: ' + str(gps.satellites_in_use), 10, 0)

oled.text('Lat: ' + latitude, 0, 18)

print('Lat: ' + latitude)

oled.text('Lon: ' + longitude, 0, 36)

print('Lon: ' + longitude)

oled.show()

Displaying GPS Data on OLED

Check location using latitude and longitude

Here’s an example of how you can use the latitude and longitude values obtained from the code and search for the location on www.latlong.net

Open a web browser and go to www.latlong.net.
Enter the latitude value in the “Latitude” input field on the website.
Enter the longitude value in the “Longitude” input field on the website.
Click on the “Convert” button on the website.
The website will display the corresponding location on the map.

3 Comments

ASHUTOSH on 10/11/2023 8:10 pm

sir it is showing data unavailable no coordinate: please help me out

- Admin on 11/11/2023 6:38 am
  
  Please go to an open place or rooftop because the signal of NEO6m GPS is very poor.
  
Bernie Branfield on 25/09/2024 11:34 pm

The GPS receiver is acquiring data, I know this because I can print lat_degs and lon_mins from micropyGPS.py module line 300 and 307 but the OLED shows ‘Data unavail’, ‘No coordinate:

When I add print commands to main.py

latitude = convert_coordinates(gps.latitude)
print(latitude)
longitude = convert_coordinates(gps.longitude)
print(longitude)

this returns

51.719337
None
51.719341
None
51.719341
None
51.719341
None
51.719341
None
51.719341
None

51.719341 is the correct latitude
It seems longitude is not reaching main.py

Thanks for any help

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Raspberry Pi Pico GPS Tracker Using NEO-6M & OLED Display

Introduction

Required Material

Raspberry Pi Pico

NEO-6M GPS Module

NEO-6M GPS module Specifications

Pinout of NEO-6M GPS Module

0.96″ OLED Display

Interfacing NEO-6M GPS Module with Raspberry Pi Pico W & OLED Display

Code & Librires

micropyGPS.py

ssd1306.py

main.py

Displaying GPS Data on OLED

Check location using latitude and longitude

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