From ff77dd120706a614b350fbafe8f3f46bbf4bc25e Mon Sep 17 00:00:00 2001
From: Marcel Walter <marcel.s.walter@gmail.com>
Date: Fri, 20 Feb 2026 12:30:10 +0100
Subject: [PATCH] handle UTF8 characters

---
 src/main.cpp | 103 +++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 100 insertions(+), 3 deletions(-)

diff --git a/src/main.cpp b/src/main.cpp
index 503b83d..eb87e78 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -430,12 +430,23 @@ String printClose(String Args)
   return Text;
 }
 
+String replaceUTF8Char(const char * message, int &i, unsigned int length);
+
 String printText(String Args)
 {
+
+  auto message = Args.c_str();
+  auto len = Args.length();
+
+  Text = "";
+  for (int i = 0; i < len; i++)
+  {
+    Text += replaceUTF8Char(message, i, len);
+  }
+
   Serial.print("Display would show '");
-  Serial.print(Args);
+  Serial.print(Text);
   Serial.println("'");
-  Text = Args;
   publishClose();
 
   return Text;
@@ -457,6 +468,92 @@ String printLate30(String Args)
   return Text;
 }
 
+String replaceUTF8Char(const char * message, int &i, unsigned int length)
+{
+  String str = "_";
+
+  if ((message[i] < 0x7E))
+  {
+    //ASCII Char
+    str = message[i];
+  }
+  else if (((i + 1) < length) && (message[i] == 0xC3) && (message[i + 1] == 0xA4))
+  {
+    str = "ae";
+    i += 1;
+  }
+  else if (((i + 1) < length) && (message[i] == 0xC3) && (message[i + 1] == 0x84))
+  {
+    str = "Ae";
+    i += 1;
+  }
+  else if (((i + 1) < length) && (message[i] == 0xC3) && (message[i + 1] == 0xB6))
+  {
+    str = "oe";
+    i += 1;
+  }
+  else if (((i + 1) < length) && (message[i] == 0xC3) && (message[i + 1] == 0x96))
+  {
+    str = "Oe";
+    i += 1;
+  }
+  else if (((i + 1) < length) && (message[i] == 0xC3) && (message[i + 1] == 0xBC))
+  {
+    str = "ue";
+    i += 1;
+  }
+  else if (((i + 1) < length) && (message[i] == 0xC3) && (message[i + 1] == 0x9C))
+  {
+    str = "Ue";
+    i += 1;
+  }
+  else if (((i + 1) < length) && (message[i] == 0xC3) && (message[i + 1] == 0x9F))
+  {
+    str = "ss";
+    i += 1;
+  }
+  else if (((i + 1) < length) && (message[i] == 0xC2) && (message[i + 1] == 0xB2))
+  {
+    str = "2";
+    i += 1;
+  }
+  else if (((i + 1) < length) && (message[i] == 0xC2) && (message[i + 1] == 0xB3))
+  {
+    str = "3";
+    i += 1;
+  }
+  else if (((i + 1) < length) && (message[i] == 0xC2) && (message[i + 1] == 0xB4))
+  {
+    str = "'";
+    i += 1;
+  }
+  else if (((i + 1) < length) && (message[i] == 0xC2) && (message[i + 1] == 0xB5))
+  {
+    str = "u";
+    i += 1;
+  }
+  else if (((i + 2) < length) && (message[i] == 0xE2) && (message[i + 1] == 0x82) && (message[i + 2] == 0xAC))
+  {
+    str = "EUR";
+    i += 2;
+  }
+  else if (message[i] & 0xC0)
+  {
+    //if utf8 char was not handled above find end of utf8 char
+    while (i < length)
+    {
+      i++;
+      if (!(message[i] & 0x80) || ((message[i] & 0xC0) == 0xC0))
+      {
+        i--;
+        break;
+      }
+    }
+  }
+
+  return str;
+}
+
 void mqttCallback(char *topic, unsigned char *message, unsigned int length)
 {
   String MessageString;
@@ -464,7 +561,7 @@ void mqttCallback(char *topic, unsigned char *message, unsigned int length)
   /* Convert all char* to Strings for simpler handling */
   for (int i = 0; i < length; i++)
   {
-    MessageString += (char) message[i];
+    MessageString += replaceUTF8Char((const char*) message, i, length);
   }
   String ToppicString(topic);