• 71k
• 5
• 76
• 256

• 301
• 1
• 8

This is an updated question with new code, taking into account your comments from last time: Car computer in python / GPS tracking

I have an old car that I use for long distance driving and have coded an onboard computer based on a Raspberry Pi 3 and a few other modules. I use a FONA 808 from Adafruit as the cellular modem (via serial), the Sparkfun NEO-M9N as a GPS sensor (i2c), an OLED display (i2c) and a small temperature sensor via 1-wire. Here is a link to a picture of the computer in action, just so you have a better picture of it: https://www.instagram.com/p/CJO9HnNneg2/

Notable improvements compared to version 1 in the old questions are (in a nutshell):

• config.ini file
• communication with remote server either per DB direct insert or per POST to a PHP script
• cleaned up use of globals, imports
• using the DRY principle as much as possible, creating new helper functions
• shortening of code where possible
• testing function for GPS module

Without further ado, here the code, split up in a few files:

car_computer.py

import os
from threading import Thread
import glob
import serial
import board
import subprocess
import smbus
import time
from time import sleep
import datetime
import configparser
import re
import urllib
from urllib import request
import random
from luma.core.interface.serial import i2c
from luma.core.render import canvas
from luma.oled.device import sh1106
from PIL import ImageFont, Image, ImageDraw
import pymysql
import csv
import json
import hashlib 
import pynmea2
from haversine import haversine, Unit
config = configparser.ConfigParser()
config.read('/home/pi/Desktop/car_computer.ini')
################## start display ##################
device = sh1106(i2c(port=1, address=config['display']['i2c_port']), rotate=0)
device.clear()
pending_redraw = False
output = Image.new("1", (128,64))
add_to_image = ImageDraw.Draw(output)
def setup_font(font_filename, size):
 return ImageFont.truetype(os.path.join(config['general']['folder'],config['general']['folder_fonts'],font_filename), size)
fa_solid = setup_font('fa-solid-900.ttf', 12)
fa_solid_largest = setup_font('fa-solid-900.ttf', 40)
text_largest = setup_font('digital-7.ttf', 58)
text_medium = setup_font('digital-7.ttf', 24)
text_small = setup_font('digital-7.ttf', 18)
icons = { #to look up the icons on FontAwesome.com, remove quote marks and \u from the search query 
 "save": "\uf56f","cloud": "\uf0c2","check": "\uf058","upload": "\uf382","no_conn": "\uf127","location": "\uf124","question": "\uf128","altitude": "\uf077","distance": "\uf1b9","temperature": "\uf2c9" }
def wipe(zone):
 add_to_image.rectangle(tuple(int(v) for v in re.findall("[0-9]+", config['display'][zone])), fill="black", outline ="black")
def icon(zone,name):
 add_to_image.text(tuple(int(v) for v in re.findall("[0-9]+", config['display'][zone])), icons[name], font=fa_solid, fill="white")
def text(zone,text,fontsize=text_medium):
 add_to_image.text(tuple(int(v) for v in re.findall("[0-9]+", config['display'][zone])), text, font=fontsize, fill="white")
################## upload data from GPS folder via FONA to MySQL ##################
def fix_nulls(s):
 return (line.replace('0円', '') for line in s)
def upload_data():
 global pending_redraw
 while True:
 sleep(5)
 current_dir = os.path.join(config['general']['folder'],config['general']['folder_data'])
 archive_dir = os.path.join(config['general']['folder'],config['general']['folder_data_archive'])
 path, dirs, files = next(os.walk(current_dir))
 file_count = len(files)
 if file_count < 2:
 print("Not enough GPS.csv files found so it's probably in use now or doesn't exist")
 return
 list_of_files = glob.glob(current_dir+"/*.csv")
 oldest_file = min(list_of_files, key=os.path.getctime)
 oldest_file_name = os.path.basename(oldest_file)
 
 try:
 openPPPD()
 
 if config['db']['mode'] == "db":
 print("mode = db")
 db = pymysql.connect(config['db']['db_host'],config['db']['db_user'],config['db']['db_pw'],config['db']['db_name'])
 cursor = db.cursor()
 csv_data = csv.reader(fix_nulls(open(oldest_file)))
 next(csv_data)
 for row in csv_data:
 if row:
 statement = 'INSERT INTO '+config['db']['db_table']+' (gps_time, gps_lat, gps_long, gps_speed) VALUES (%s, %s, %s, %s)'
 cursor.execute(statement,row)
 print("Committing to db")
 db.commit()
 cursor.close()
 
 if config['db']['mode'] == "server":
 print("mode = server")
 csv_data = csv.reader(fix_nulls(open(oldest_file)))
 next(csv_data)
 row_nb = 1
 row_data = {}
 rows_encoded_nb = 1
 rows_encoded = {}
 for row in csv_data:
 if row:
 row_data[row_nb] = {'gps_time': int(row[0]), 'gps_lat' : round(float(row[1]), 5), 'gps_long' : round(float(row[2]), 5), 'gps_speed' : round(float(row[3]), 1)}
 if row_nb % int(config['db']['server_batchsize']) == 0:
 rows_encoded[rows_encoded_nb] = row_data
 rows_encoded_nb +=1
 row_data = {}
 row_nb +=1
 rows_encoded[rows_encoded_nb] = row_data
 row_data = {}
 
 for i in rows_encoded : 
 checksum = hashlib.md5(str(rows_encoded[i]).encode())
 checksum = checksum.hexdigest()
 
 req = request.Request(config['db']['server_addr'], method="POST")
 req.add_header('Content-Type', 'application/json')
 data = {
 "hash": checksum,
 "ID": config['db']['server_ID'],
 "pw": config['db']['server_pw'],
 "data": rows_encoded[i]
 }
 data = json.dumps(data)
 data = data.encode()
 r = request.urlopen(req, data=data)
 print(r.read())
 
 #sleep(1)
 closePPPD()
 print("Successfully committed to db")
 wipe('GPRS_ZONE')
 icon('GPRS_START',"check")
 pending_redraw = True
 os.rename(current_dir+"/"+oldest_file_name, archive_dir+"/archive_"+oldest_file_name) 
 sleep(60)
 wipe('GPRS_ZONE')
 
 except Exception as e:
 print("Database error:", e)
 wipe('GPRS_ZONE')
 icon('GPRS_START',"no_conn")
 pending_redraw = True
 closePPPD()
 sleep(60)
 wipe('GPRS_ZONE')
 pending_redraw = True
 return
 
 sleep(300)
 
################## config and start GPS ##################
BUS = None
reading_nr = 1
reading_nr_upload = 1
reading_nr_upload_nbrowsinlog = 0
total_km = 0
prev_lat = 0
prev_long = 0
def connectBus():
 global BUS
 BUS = smbus.SMBus(1)
def debug_gps():
 sleep(1)
 time = datetime.datetime.now()
 gga1 = pynmea2.GGA('GN', 'GGA', (time.strftime("%H%M%S"), '1929.045', 'S', '02410.516', 'E', '1', '04', '2.6', '69.00', 'M', '-33.9', 'M', '', '0000'))
 gga2 = pynmea2.GGA('GN', 'GGA', (time.strftime("%H%M%S"), '1929.075', 'S', '02410.506', 'E', '1', '04', '2.6', '73.00', 'M', '-33.9', 'M', '', '0000'))
 rmc1 = pynmea2.RMC('GN', 'RMC', (time.strftime("%H%M%S"), 'A', '1929.055', 'S', '02411.516', 'E', '28', '076.2', time.strftime("%d%m%y"), 'A'))
 rmc2 = pynmea2.RMC('GN', 'RMC', (time.strftime("%H%M%S"), 'A', '1929.045', 'S', '02411.506', 'E', '29', '076.2', time.strftime("%d%m%y"), 'A'))
 nmea = [gga1,rmc1,gga2,rmc2]
 return str(random.choice(nmea))
def parseResponse(gpsLine):
 global pending_redraw
 gpsChars = ''.join(chr(c) for c in gpsLine)
 
 ##### uncomment only for testing when the GPS chip has no reception #####
 gpsChars = debug_gps()
 #print(gpsChars)
 
 if "GGA" in gpsChars:
 if ",1," not in gpsChars:
 print("GGA?")
 wipe('STATUS_ICON_ZONE')
 wipe('STATUS_ZONE')
 icon('STATUS_ICON_START', "location")
 icon('STATUS_START', "question")
 pending_redraw = True
 sleep(1)
 return False
 try:
 nmea = pynmea2.parse(gpsChars, check=True)
 if "0.0" in str(nmea.latitude) or "0.0" in str(nmea.longitude):
 return False
 
 #show that we have a location and delete whatever was there
 wipe('STATUS_ICON_ZONE')
 icon('STATUS_ICON_START', "location")
 wipe('STATUS_ZONE')
 
 ## update altitude
 icon('ALTI_ICON_START', "altitude")
 wipe('ALTI_ZONE')
 text('ALTI_START', str('%.0f'%(nmea.altitude)))
 
 ## update total distance
 global reading_nr
 global total_km
 global prev_lat
 global prev_long
 dist = 0
 if reading_nr != 1:
 dist = haversine(((float(prev_lat)), (float(prev_long))), ((float(nmea.latitude)), (float(nmea.longitude))))
 total_km = total_km+dist
 icon('DIST_ICON_START', "distance")
 wipe('DIST_ZONE')
 text('DIST_START', "%0.1f" % total_km)
 prev_lat = nmea.latitude
 prev_long = nmea.longitude
 
 pending_redraw = True
 reading_nr +=1
 
 except Exception as e:
 print("GGA parse error:", e)
 wipe('STATUS_ZONE')
 pending_redraw = True
 pass
 
 if "RMC" in gpsChars:
 if ",A," not in gpsChars: # 1 for GGA, A for RMC
 print("RMC?")
 wipe('STATUS_ICON_ZONE')
 wipe('STATUS_ZONE')
 icon('STATUS_ICON_START', "location")
 icon('STATUS_START', "question")
 pending_redraw = True
 sleep(1)
 return False
 try:
 nmea = pynmea2.parse(gpsChars, check=True)
 if "0.0" in str(nmea.latitude) or "0.0" in str(nmea.longitude):
 return False
 
 #show that we have a location and delete whatever was there
 wipe('STATUS_ICON_ZONE')
 icon('STATUS_ICON_START', "location")
 wipe('STATUS_ZONE')
 
 ## update speed
 wipe('SPEED_ZONE')
 text('SPEED_START', str('%.0f'%(nmea.spd_over_grnd*1.852)), fontsize=text_largest)
 
 ## log every log_frequency nth GPS coordinate in CSV file
 global reading_nr_upload
 global reading_nr_upload_nbrowsinlog
 if reading_nr_upload % int(config['gps']['log_frequency']) == 0:
 t = datetime.datetime.combine(nmea.datestamp, nmea.timestamp).strftime("%s")
 d = datetime.datetime.combine(nmea.datestamp, nmea.timestamp).strftime("%Y%m%d%H")
 filename = os.path.join(config['general']['folder'],config['general']['folder_data'],'gps_' + d + '.csv')
 with open(filename, 'a', newline='') as csvfile:
 gps_writer = csv.writer(csvfile, delimiter=',', quotechar='|', quoting=csv.QUOTE_MINIMAL)
 gps_writer.writerow([t, nmea.latitude, nmea.longitude, nmea.spd_over_grnd*1.852])
 reading_nr_upload_nbrowsinlog +=1
 #print("Added to log. Total in Log from this session is", reading_nr_upload_nbrowsinlog)
 wipe('STATUS_ZONE')
 icon('STATUS_START',"save")
 reading_nr_upload +=1
 pending_redraw = True
 
 except Exception as e:
 print("RMC parse error:", e)
 wipe('STATUS_ZONE')
 pending_redraw = True
 pass
def readGPS():
 c = None
 response = []
 try:
 while True: # Newline, or bad char.
 global BUS
 c = BUS.read_byte(int(config['gps']['i2c_port'], 16))
 if c == 255:
 return False
 elif c == 10:
 break
 else:
 response.append(c)
 parseResponse(response)
 except IOError:
 time.sleep(0.5)
 connectBus()
connectBus()
def updateGPS():
 while True:
 readGPS()
################## config external thermometer ##################
def update_temp_ext(temp_signature='t=', update_interval=config['temp_ext']['update_interval']):
 global pending_redraw
 icon('TEMP_ICON_START', "temperature")
 base_dir = config['temp_ext']['w1_folder']
 device_folder = glob.glob(base_dir + '28*')[0]
 device_file = device_folder + '/w1_slave'
 while True:
 f = open(device_file, 'r')
 lines = f.readlines()
 f.close()
 equals_pos = lines[1].find(temp_signature)
 if equals_pos != -1:
 temp_string = lines[1][equals_pos+2:]
 temp_c = round(float(temp_string) / 1000.0)
 wipe('TEMP_ZONE')
 text('TEMP_START', str(temp_c))
 pending_redraw = True
 time.sleep(int(update_interval))
 
################## update display ##################
def update_display():
 sleep(0.5)
 while True:
 global pending_redraw
 if pending_redraw:
 device.display(output)
 pending_redraw = False
 time.sleep(0.2)
 
################## start cellular connection ################## 
def openPPPD():
 subprocess.call("sudo pon fona", shell=True)
 print("FONA on")
 wipe('GPRS_ZONE')
 icon('GPRS_START', "cloud")
 global pending_redraw
 pending_redraw = True
 sleep(20)
 try:
 urllib.request.urlopen(config['db']['ping'])
 print("Connection is on")
 wipe('GPRS_ZONE')
 icon('GPRS_START', "upload")
 pending_redraw = True
 return True
 except:
 print("Connection error")
 wipe('GPRS_ZONE')
 icon('GPRS_START', "no_conn")
 pending_redraw = True
 return False
# Stop PPPD
def closePPPD():
 print("turning off PPPD")
 subprocess.call("sudo poff fona", shell=True)
 print("turned off")
 return True
 
################## threading and program execution ##################
if __name__ == '__main__':
 temp_ext_thread = Thread(target = update_temp_ext)
 display_thread = Thread(target=update_display)
 gps_thread = Thread(target = updateGPS)
 data_thread = Thread(target = upload_data)
 
 display_thread.start() 
 gps_thread.start()
 data_thread.start()
 temp_ext_thread.start()
 
 display_thread.join()

car_computer.ini

[general]
folder = /home/pi/Desktop
folder_fonts = fonts
folder_data = data/gps
folder_data_archive = data/gps/archive
[db]
mode = server
ping = https://XXX
db_host = XXX
db_user = XXX
db_pw = XXX
db_name = XXX
db_table = gps_data
server_addr = https://www.XXX.com/gps_logger.php
server_batchsize = 50
server_ID = XXX
server_pw = XXX
[display]
i2c_port = 0x3c
### coordinates always: padding-left, padding-top. the first pair of zone is mostly = start (except to offset small icons)
# temp_ext
TEMP_ZONE = [(14,44), (36,64)]
TEMP_START = (14,44)
TEMP_ICON_ZONE = [(0,48), (15,64)]
TEMP_ICON_START = (3,48)
# alti
ALTI_ZONE = [(14,22), (69,40)]
ALTI_START = (14,22)
ALTI_ICON_ZONE = [(0,24), (15,40)]
ALTI_ICON_START = (0,26)
# distance
DIST_ZONE = [(14,0), (69,21)]
DIST_START = (14,0)
DIST_ICON_ZONE = [(0,4), (15,21)]
DIST_ICON_START = (0,4)
# speed
SPEED_ZONE = [(66,0), (128,45)]
SPEED_START = (66,0)
# GPRS status
GPRS_ZONE = [(114,46), (128,64)]
GPRS_START = (114,50)
# GPS status, incl. GPS startup icon
STATUS_ICON_ZONE = [(70,50), (88,64)]
STATUS_ICON_START = (70,50)
STATUS_ZONE = [(86,46), (113,64)]
STATUS_START_TEXT = (86,46)
STATUS_START = (86,50)
[gps]
i2c_port = 0x42
log_frequency = 5
[temp_ext]
update_interval = 30
w1_folder = /sys/bus/w1/devices/

gps_logger.php

<?php 
$mysqli = new mysqli($hostname_db, $username_db, $password_db,$database_db);
$json = file_get_contents('php://input');
if($data = json_decode($json)) {
 $sql = "SELECT * FROM gps_computers WHERE gc_ID = ? AND gc_pw = ?";
 $statement = $mysqli->prepare($sql);
 $statement->bind_param('is', $data->ID, $data->pw);
 if(!$statement->execute()) { die("Query error: ".$statement->error); } 
 $auth = $statement->get_result();
 $totalRows_auth = $auth->num_rows;
 if($totalRows_auth == 1) {
 echo "";
 } else {
 echo "no auth match found";
 die;
 }
 $i = 0;
 foreach ($data->data as $key => $record) {
 $sql = "SELECT * FROM gps_data WHERE gps_time = ? AND gps_computerID = ?";
 $statement = $mysqli->prepare($sql);
 $statement->bind_param('ii', $record->gps_time, $data->ID);
 if(!$statement->execute()) { die("Query error: ".$statement->error); } 
 $doublecheck = $statement->get_result();
 $totalRows_doublecheck = $doublecheck->num_rows;
 if($totalRows_doublecheck != 1) {
 $i++;
 $sql = "INSERT INTO `gps_data` (`gps_time`, `gps_lat`, `gps_long`, `gps_speed`, `gps_computerID`) VALUES (?, ?, ?, ?, ?);";
 $statement = $mysqli->prepare($sql);
 $statement->bind_param('isssi', $record->gps_time, $record->gps_lat, $record->gps_long, $record->gps_speed, $data->ID);
 if(!$statement->execute()) { die("Query error: ".$statement->error); } 
 }
 }
 echo $i." records inserted";
} else {
 echo "error reading json";
}
?>

I have to say I'm quite proud of how it's turned out! Happy to edit the question if you want more info to better help :)