Wireless MQTT Data Display

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It's Node Red. I'll send you the script when I get home.

Here's the script. It is super simple - just connect to a TCP port (which is configured in OpenPlotter to send out NMEA strings), and output to MQTT.

Code:

[
   {
       "id": "d7c474e4.e397e8",
       "type": "tab",
       "label": "Flow 1",
       "disabled": false,
       "info": ""
   },
   {
       "id": "2bb5840f.59abac",
       "type": "debug",
       "z": "d7c474e4.e397e8",
       "name": "",
       "active": true,
       "tosidebar": true,
       "console": false,
       "tostatus": false,
       "complete": "false",
       "x": 719,
       "y": 167,
       "wires": []
   },
   {
       "id": "a00c6215.e7772",
       "type": "mqtt out",
       "z": "d7c474e4.e397e8",
       "name": "",
       "topic": "inTopic",
       "qos": "",
       "retain": "",
       "broker": "30d4d987.926566",
       "x": 990,
       "y": 348,
       "wires": []
   },
   {
       "id": "1e891e14.3239c2",
       "type": "tcp in",
       "z": "d7c474e4.e397e8",
       "name": "",
       "server": "client",
       "host": "127.0.0.1",
       "port": "44444",
       "datamode": "stream",
       "datatype": "utf8",
       "newline": "\\n",
       "topic": "",
       "base64": false,
       "x": 265,
       "y": 326,
       "wires": [
           [
               "a00c6215.e7772",
               "2bb5840f.59abac"
           ]
       ]
   },
   {
       "id": "30d4d987.926566",
       "type": "mqtt-broker",
       "z": "",
       "name": "",
       "broker": "<YOUR MQTT BROKER ADDRESS>",
       "port": "1883",
       "clientid": "",
       "usetls": false,
       "compatmode": true,
       "keepalive": "60",
       "cleansession": true,
       "birthTopic": "",
       "birthQos": "0",
       "birthPayload": "howdy partner",
       "closeTopic": "",
       "closeQos": "0",
       "closePayload": "",
       "willTopic": "",
       "willQos": "0",
       "willPayload": ""
   }
]

Here is the updated code. I put in a watchdog timer to restart the system if it doesn't get a WiFi connection in 30 seconds. This helps because this device powers up at the same time as my OpenPlotter computer, which takes slightly more than 30 seconds to boot and start OpenPlotter.

Code:

/*
Basic MQTT Connection for NMEA
*/
#include <WiFi.h>
#include <WiFiClient.h>
#include <PubSubClient.h>
#include <TinyGPS++.h>
#include <LiquidCrystal_I2C.h>


// Update these with values suitable for your network.

const char* ssid = "<YOUR SSID>";
const char* password = "<YOUR WIFI PASSWORD>";
const char* mqtt_server = "10.10.10.1";
const char* mqttUser = "pi";
const char* mqttPassword = "<YOUR MQTT PASSWORD>";

// The TinyGPS++ object
TinyGPSPlus gps;

WiFiClient espClient;
PubSubClient client(espClient);
long lastMsg = 0;
char msg[50];
int value = 0;

// set the LCD number of columns and rows
int lcdColumns = 20;
int lcdRows = 4;

String DBT = "";
String northSouth = "N ";
String eastWest = "E ";
double latRaw;
double lonRaw;
String latiTude = "";
String longiTude = "";

// set LCD address, number of columns and rows
// if you don't know your display address, run an I2C scanner sketch
LiquidCrystal_I2C lcd(0x27, lcdColumns, lcdRows);

//Create the knot character
byte customChar[8] = {
 0b10000,
 0b10100,
 0b11000,
 0b10100,
 0b00010,
 0b00111,
 0b00010,
 0b00011
};

void setup_wifi() {

 delay(10);
 // We start by connecting to a WiFi network
 Serial.println();
 Serial.print("Connecting to ");
 lcd.setCursor(0,0);
 lcd.print("SSID: ");
 Serial.println(ssid);
 lcd.setCursor(7,0);
 lcd.print(ssid);

 WiFi.begin(ssid, password);
 int dot_cur = 0;
 lcd.setCursor(0,1);
 int reset_index = 0;
 while (WiFi.status() != WL_CONNECTED) {
   delay(500);
   Serial.print(".");
   lcd.print(".");
   //If WiFi doesn't connect in 30 seconds, do a software reset
   reset_index ++;
   if (reset_index > 60) {
     Serial.println("WIFI Failed - restarting");
     lcd.setCursor(0,2);
     lcd.print("No WIFI: restarting");
     ESP.restart();
   }
 }

 randomSeed(micros());

 Serial.println("");
 lcd.clear();
 Serial.println("WiFi connected");
 lcd.setCursor(0,0);
 lcd.print("WiFi connected");
 Serial.println("IP address: ");
 lcd.setCursor(0,2);
 lcd.print("IP: ");
 Serial.println(WiFi.localIP());
 lcd.setCursor(5,2);
 lcd.print(WiFi.localIP());
}

void setup_lcd(){
 // initialize LCD
 lcd.init();
 // turn on LCD backlight                      
 lcd.backlight();
 // set cursor to first column, first row
 lcd.setCursor(0, 0);
}

void callback(char* topic, byte* payload, unsigned int length) {
 for (int i=0;i<length;i++) {
   if (gps.encode(*payload++))
     displayInfo();
 }
 Serial.println();
}

void reconnect() {
 // Loop until we're reconnected
 while (!client.connected()) {
   Serial.print("Attempting MQTT connection...");
   // Create a random client ID
   String clientId = "ESP32Client-";
   clientId += String(random(0xffff), HEX);
   // Attempt to connect
   if (client.connect(clientId.c_str(),mqttUser,mqttPassword)) {
     Serial.println("connected");
     client.subscribe("inTopic");
     //arrow characters in the upper right when MQTT is connected
     lcd.setCursor(19,0);
     lcd.print(char(127));
     lcd.setCursor(19,1);
     lcd.print(char(126));
     delay(500);
   } else {
     Serial.print("failed, rc=");
     Serial.print(client.state());
     Serial.println(" try again in 5 seconds");
     lcd.setCursor(0,1);
     lcd.print("MQTT Failed");
     lcd.setCursor(0,2);
     lcd.print("rc=");
     lcd.print(client.state());
     // Wait 5 seconds before retrying
     delay(5000);
   }
 }
}

void setup() {
 Serial.begin(115200);
 setup_lcd();
 // create a new custom character for knot
 lcd.createChar(0, customChar);
 setup_wifi();
 client.setServer(mqtt_server, 1883);
 client.setCallback(callback);
 //Delay 5 secs so we can see what happened
 delay (5000);
 lcd.clear();
}

void loop() {

 if (!client.connected()) {
   reconnect();
 }
 client.loop();
}

void displayInfo()
{
 Serial.print(F("Location: "));
 if (gps.location.isValid())
 {
   latRaw = gps.location.lat();
   Serial.print(latRaw);
   if (latRaw < 0){
     northSouth = "S ";
   }
   else
   {
     northSouth = "N ";
   }
   latRaw = abs(latRaw);
   int latDeg = latRaw;
   Serial.println(latDeg);
   double latMins = (latRaw - latDeg) * 60;
   Serial.println(latMins);
   latiTude = northSouth;
   if (latDeg < 100){
     latiTude += " ";
   }
   else if (latDeg < 10) {
     latiTude += "  ";
   }
   latiTude += latDeg;
   latiTude += char(223);
   if (latMins <10)
     latiTude += " ";
   latiTude += String(latMins,3);
   latiTude += "\'  ";
   lcd.setCursor(0,0);
   lcd.print("LAT: ");
   lcd.print(latiTude);
   Serial.print(F(","));
   Serial.print(gps.location.lng(), 6);
   lonRaw = gps.location.lng();
   if (lonRaw < 0){
     eastWest = "W ";    
   }
   else
   {
     eastWest = "E ";
   }
   lonRaw = abs(lonRaw);
   int lonDeg = lonRaw;
   double lonMins = (lonRaw - lonDeg) * 60;
   longiTude = eastWest;
   if (lonDeg < 100){
     longiTude += " ";
   }
   else if (lonDeg < 10) {
     longiTude += "  ";
   }
   longiTude += lonDeg;
   longiTude += char(223);
   if (lonMins < 10)
     longiTude += " ";
   longiTude += String(lonMins,3);
   longiTude += "\'  ";
   lcd.setCursor(0,1);
   lcd.print("LON: ");
   lcd.print(longiTude);
 }
 else
 {
   Serial.print(F("INVALID"));
   lcd.setCursor(0,0);
   lcd.print("========NAN========");
   lcd.setCursor(0,1);
   lcd.print("========NAN========");
 }

 if (gps.speed.isValid()) {
   lcd.setCursor(10,2);
   lcd.print("SOG: ");
   lcd.print(gps.speed.knots(),1);
   //lcd.print("K");
   lcd.write((uint8_t)0);
   if (gps.speed.knots() < 10){
     lcd.print(" ");
   }
 }
 else
 {
   Serial.print(F("INVALID"));
   lcd.setCursor(10,2);
   lcd.print("===NAN===");
 }

 if (gps.course.isValid()){
   Serial.println("");
   Serial.print(F("COG="));
   lcd.setCursor(0,2);
   lcd.print("COG: ");
   Serial.println(gps.course.deg());
   lcd.print(gps.course.deg(), 0);
   lcd.print(char(223));
   if (gps.course.deg()<10){
     lcd.print("   ");    
   }
   else if (gps.course.deg()<100){
     lcd.print("  ");
   }
 }
   else
 {
   Serial.print(F("INVALID"));
   lcd.setCursor(0,2);
   lcd.print("==NAN==");
 }

 Serial.print(F("  Date/Time: "));
 if (gps.date.isValid())
 {
   lcd.setCursor(10,3);
   Serial.print(gps.date.month());
   lcd.print(gps.date.month());
   Serial.print(F("/"));
   lcd.print(F("/"));
   Serial.print(gps.date.day());
   lcd.print(gps.date.day());
   Serial.print(F("/"));
   lcd.print(F("/"));    
   Serial.print(gps.date.year());
   lcd.print(gps.date.year());
 }
 else
 {
   Serial.print(F("INVALID"));
   lcd.setCursor(10,3);
   lcd.print("===NAN===");
 }

 Serial.print(F(" "));
 if (gps.time.isValid())
 {
   lcd.setCursor(0,3);
   if (gps.time.hour() < 10) {
     Serial.print(F("0"));
     lcd.print(F("0"));
   }
   lcd.print(gps.time.hour());
   Serial.print(gps.time.hour());
   Serial.print(F(":"));
   lcd.print(":");
   if (gps.time.minute() < 10){
     Serial.print(F("0"));
     lcd.print(F("0"));
   }
   Serial.print(gps.time.minute());
   lcd.print(gps.time.minute());
   Serial.print(F(":"));
   lcd.print(":");
   if (gps.time.second() < 10) {
     Serial.print(F("0"));
     lcd.print(F("0"));
   }
   Serial.print(gps.time.second());
   lcd.print(gps.time.second());
   Serial.print(F("."));
   if (gps.time.centisecond() < 10){
     Serial.print(F("0"));
   }
   Serial.print(gps.time.centisecond());
   lcd.print("Z");
 }
 else
 {
   Serial.print(F("INVALID"));
   lcd.setCursor(0,3);
   lcd.print("===NAN===");
 }

 Serial.println();
}