End Device Traceur GPS

- +5 Volts
- GND
- Neo TX - GPIO 2
- Neo RX - GPIO 0

#define RXD2 0
#define TXD2 4
#define GPS_BAUD 9600
HardwareSerial ss(2);
ss.begin(GPS_BAUD, SERIAL_8N1, RXD2, TXD2);

{
"end_device_ids":{"device_id":"on4kch-gps","application_ids":{"application_id":"ttgo32-jpco"},"dev_eui":"70B3D57ED00700D7","join_eui":"0000000000000000","dev_addr":"260B1741"},
"correlation_ids":["gs:uplink:01M027FH7HJSB4HH17N9G8NDM8"],
"received_at":"2026-08-15T08:09:15.017387224Z",
"join_accept":{"session_key_id":"AaAEd8T3LN2jiZ90gGrkew==","received_at":"2026-08-15T08:09:13.201869521Z"}
}

{
"end_device_ids":{"device_id":"on4kch-gps","application_ids":{"application_id":"ttgo32-jpco"},
"dev_eui":"70B3D57ED00700D7",
"join_eui":"0000000000000000",
"dev_addr":"260B1741"},
"correlation_ids":["gs:uplink:01M027FH7HJSB4HH17N9G8NDM8"],
"received_at":"2026-08-15T08:09:15.017387224Z",
"join_accept":{"session_key_id":"AaAEd8T3LN2jiZ90gGrkew==","received_at":"2026-08-15T08:09:13.201869521Z"}
}

{
"end_device_ids":{"device_id":"on4kch-gps","application_ids":{"application_id":"ttgo32-jpco"},"dev_eui":"70B3D57ED00700D7","join_eui":"0000000000000000","dev_addr":"260B1741"},
"correlation_ids":["gs:uplink:01M027TVXKCAQ67M8N6E6ZMQDS"],
"received_at":"2026-08-15T08:15:24.801482345Z",
"location_solved":{"service":"frm-payload","location":{"latitude":50.73268298701544,"longitude":5.684255700365071,"altitude":56,"source":"SOURCE_GPS"}}
}

#!/usr/bin/python
import paho.mqtt.client as mqtt
import json
import rrdtool
import queue
import sys
import requests
import asyncio
import random
import time
import aprslib
import mariadb
from datetime import datetime

msgs = queue.Queue()

hostname="IP broker"
remote_user="username"
remote_password="password"
topic = [("ttn/on4kch-gps/location/solved",1)] # we are listening to the location topic only
post_interval = 600

f = open("/var/log/rrd/ttn.log","a") # log file


def on_subscribe(client, userdata, mid, granted_qos):
    # Since we subscribed only for a single channel, reason_code_list contains
    # a single entry
    #if reason_code_list[0].is_failure:
    #    print(f"Broker rejected you subscription: {reason_code_list[0]}")
    #else:
    f.write(f"Subscribed topic msg ID: {mid} with QOS: {granted_qos}\n")
    f.flush()

def on_unsubscribe(client, userdata, mid, gtanted_qos):
    # Be careful, the reason_code_list is only present in MQTTv5.
    # In MQTTv3 it will always be empty
    #if len(reason_code_list) == 0 or not reason_code_list[0].is_failure:
    #    print("unsubscribe succeeded (if SUBACK is received in MQTTv3 it success)")
    #else:
    f.write(f"Broker replied with failure: {reason_code_list[0]}\n")
    f.flush()
    client.disconnect()
def on_message(client,userdata,message):
    msgs.put(message)

def workq(message):
# process the incoming mqtt message

# process only messages from the right topic
# ttn/on4kch-gps/location/solved is a message from the thing network
    parsed = message.payload.decode("utf-8")
    json_object = json.loads(parsed)

    # check the topic        
    if (str(message.topic).startswith("ttn/on4kch-gps/location/solved")):
  
        parsed = message.payload.decode("utf-8")
        json_object = json.loads(parsed)
        try:
            lat = json_object['location_solved']['location']['latitude']
            long = json_object['location_solved']['location']['longitude']
            alt = json_object['location_solved']['location']['altitude']
            SQL=f"INSERT INTO `on4kch-gps` (`latitude`, `longitude`, `altitude`) VALUES ('{lat}','{long}','{alt}')"
            print(SQL)
            insertdb(SQL)
        except:
            f.write("error in SQL insert\n") 

    f.flush()
    
def on_connect(client, flags, reason_code, properties=None):
        client.subscribe(topic)

def on_disconnect(client, flags, reason_code, properties=None):
        f.write("mqtt disconnected\n")
        f.flush()

def insertdb(SQL):
    cursor = connection.cursor()
    cursor.execute(SQL)
    connection.commit()
    cursor.close()

def Now():
    return datetime.now().strftime("%c")

# broker connexion related

client_id = f'collector_ttn-{random.randint(0, 1000)}'
mqttc = mqtt.Client(mqtt.CallbackAPIVersion.VERSION1,client_id)
mqttc.username_pw_set(remote_user, remote_password)
mqttc.connect(hostname,1883)
mqttc.on_connect = on_connect
mqttc.on_disconnect = on_disconnect
mqttc.on_message = on_message
mqttc.on_subscribe = on_subscribe
mqttc.on_unsubscribe = on_unsubscribe

f.write(Now()+" Starting collector_ttn.py\n")
f.flush()

# mqtt loop, process reconnected if necessary
mqttc.loop_start()

# connect the mariqdb server

try:
    # Connect to MariaDB
    connection = mariadb.connect(
        user="username",
        password="password",
        host="mariadb_server_name",
        port=3306,
        database="TTN"
    )
    # make sure it reconnect if disconnect unexpectedly
    connection.auto_reconnect = True
    
    f.write(Now()+" Connected to MariaDB TTN successfully!\n")
    f.write(Now()+f" MariaDB version: {connection.server_version}\n")
    

except mariadb.Error as e:
    f.write(Now()+f" Error connecting to MariaDB: {e}\n")
    sys.exit(1)

f.flush() # make sure message are written to the log file

cur_time = datetime.now() # initialize the current time


# process the messages inserted in the queue by the mqtt message receiver
# loop indefinitely

while(True):
    if (not msgs.empty()):
        #f.write("queue size: "+str(msgs.qsize())+" ")
        msg = msgs.get()
        workq(msg)
    time.sleep(0.001)