More precise wheel circumference, and added mDNS

ESP32/src/vehicle-monitor.cpp

@@ -9,6 +9,7 @@
 #include "Info.h"
 #include "utils.h"
 
+#include <ESPmDNS.h>
 #include <WiFi.h>
 #include <WiFiMulti.h>
 #include <FS.h>
@@ -37,9 +38,11 @@ const int8_t debugLedPin = 2;
 const int8_t I2C_SDA = 15;
 const int8_t I2C_SCL = 4;
 
-const float wheelDiameterInches = 20;
+//const float wheelDiameterInches = 20;
+//const float wheelTotalCircumeferenceMeters = wheelDiameterInches * 0.0254f * 3.1415f
+const float wheelTotalCircumeferenceMeters = 1.60f; // measuring how much the vehicle advances for one turn of the wheel is more precise than calculating from the wheel diameter
 const int numImpulsesPerTurn = 2;
-const float wheelCircumferenceMeters = wheelDiameterInches * 0.0254f * 3.1415f / (float)numImpulsesPerTurn;
+const float wheelCircumferenceMeters = wheelTotalCircumeferenceMeters / (float)numImpulsesPerTurn;
 const uint32_t wheelCircumferenceMillimeters = (uint32_t)(wheelCircumferenceMeters * 1000.0f + 0.5f);
 
 Status status;
@@ -188,6 +191,7 @@ void setup()
 	}
 
 	// Set WiFi mode to both AccessPoint and Station
+	WiFi.setHostname("vmon"); // this doesn't work when connecting to a mobile android hotspot (it can't resolve the hostname), but it should work with most routers allowing to access the app on https://vmon
 	WiFi.mode(WIFI_AP_STA);
 
 	// Create the WiFi Access Point
@@ -205,6 +209,9 @@ void setup()
 	// Also connect as a station (if the configured remote access point is in range)
 	connectWifi();
 	
+	Serial.print("hostname: ");
+	Serial.println(WiFi.getHostname());
+
 	OTA.begin();
 
 	#if ENABLE_GPS_COORDINATES
@@ -236,6 +243,18 @@ void handle_wifi_connection()
 			DebugLog.print(WiFi.SSID().c_str());
 			DebugLog.print("), ip=");
 			DebugLog.println(WiFi.localIP());
+
+			// mDNS can help in case the router does not correctly handle local DNS after assigning an IP address via DHCP
+			// It works by broadcasting a request for a host name on the local network, and the device directly sends its IP address in response
+			// Unfortunately, some systems do not support mDNS (e.g. Android), so they won't use it at all.
+			// To access through mDNS, remember to add the ".local" suffix to the host name (for example if host name is "vmon", access it at URL "https://vmon.local")
+			Serial.print("Starting mDNS server with hostname \"");
+			Serial.print(WiFi.getHostname());
+			Serial.println("\"");
+			if(!MDNS.begin(WiFi.getHostname()))
+			{
+				 Serial.println("Error starting mDNS");
+			}
 		}
 		else if(newWifiStatus == WL_DISCONNECTED)
 		{