2022-06-15, 11:18 AM
I Would like to forward the output from this gps module to signalk using i2c. I am sure I could use the user option but the i2c makes wiring a lot easier.
I am able to get the a parsed output using the example code from adafruit but can’t find a way for gpsd or signalk to read it.
I presume I have to pipe the output to a fake serial port but can’t find a way to do it.
Thank you
Phil
I am able to get the a parsed output using the example code from adafruit but can’t find a way for gpsd or signalk to read it.
I presume I have to pipe the output to a fake serial port but can’t find a way to do it.
Thank you
Phil
Code:
# SPDX-FileCopyrightText: 2021 ladyada for Adafruit Industries
# SPDX-License-Identifier: MIT
# Simple GPS module demonstration.
# Will print NMEA sentences received from the GPS, great for testing connection
# Uses the GPS to send some commands, then reads directly from the GPS
import time
import board
import busio
import adafruit_gps
# Create a serial connection for the GPS connection using default speed and
# a slightly higher timeout (GPS modules typically update once a second).
# These are the defaults you should use for the GPS FeatherWing.
# For other boards set RX = GPS module TX, and TX = GPS module RX pins.
#uart = busio.UART(board.TX, board.RX, baudrate=9600, timeout=10)
# for a computer, use the pyserial library for uart access
# import serial
# uart = serial.Serial("/dev/ttyUSB0", baudrate=9600, timeout=10)
# If using I2C, we'll create an I2C interface to talk to using default pins
i2c = board.I2C()
# Create a GPS module instance.
#gps = adafruit_gps.GPS(uart) # Use UART/pyserial
gps = adafruit_gps.GPS_GtopI2C(i2c) # Use I2C interface
# Initialize the GPS module by changing what data it sends and at what rate.
# These are NMEA extensions for PMTK_314_SET_NMEA_OUTPUT and
# PMTK_220_SET_NMEA_UPDATERATE but you can send anything from here to adjust
# the GPS module behavior:
# https://cdn-shop.adafruit.com/datasheets/PMTK_A11.pdf
# Turn on the basic GGA and RMC info (what you typically want)
gps.send_command(b"PMTK314,0,1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0")
# Turn on just minimum info (RMC only, location):
# gps.send_command(b'PMTK314,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0')
# Turn off everything:
# gps.send_command(b'PMTK314,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0')
# Tuen on everything (not all of it is parsed!)
# gps.send_command(b'PMTK314,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0')
# Set update rate to once a second (1hz) which is what you typically want.
gps.send_command(b"PMTK220,1000")
# Or decrease to once every two seconds by doubling the millisecond value.
# Be sure to also increase your UART timeout above!
# gps.send_command(b'PMTK220,2000')
# You can also speed up the rate, but don't go too fast or else you can lose
# data during parsing. This would be twice a second (2hz, 500ms delay):
# gps.send_command(b'PMTK220,500')
# Main loop runs forever printing data as it comes in
timestamp = time.monotonic()
while True:
data = gps.read(32) # read up to 32 bytes
# print(data) # this is a bytearray type
if data is not None:
# convert bytearray to string
data_string = "".join([chr(b) for b in data])
print(data_string, end="")
if time.monotonic() - timestamp > 5:
# every 5 seconds...
gps.send_command(b"PMTK605") # request firmware version
timestamp = time.monotonic()