meshcore-dev · ViezeVingertjes · Aug 18, 2026
diff --git a/examples/companion_radio/main.cpp b/examples/companion_radio/main.cpp
@@ -1,6 +1,7 @@
 #include <Arduino.h>   // needed for PlatformIO
 #include <Mesh.h>
 #include "MyMesh.h"
+#include <helpers/RadioFailIndicator.h>
 
 // Believe it or not, this std C function is busted on some platforms!
 static uint32_t _atoi(const char* sp) {
@@ -104,7 +105,7 @@ MyMesh the_mesh(radio_driver, fast_rng, rtc_clock, tables, store
 /* END GLOBAL OBJECTS */
 
 void halt() {
-  while (1) ;
+  haltWithRadioFailure();
 }
 
 /* WIFI RECONNECT TRACKERS */
@@ -134,7 +135,12 @@ void setup() {
   }
 #endif
 
-  if (!radio_init()) { halt(); }
+  if (!radio_init()) {
+  #ifdef DISPLAY_CLASS
+    showRadioErrorOnDisplay(disp);
+  #endif
+    halt();
+  }
 
   fast_rng.begin(radio_driver.getRngSeed());
 

diff --git a/examples/kiss_modem/main.cpp b/examples/kiss_modem/main.cpp
@@ -2,6 +2,7 @@
 #include <target.h>
 #include <helpers/ArduinoHelpers.h>
 #include <helpers/IdentityStore.h>
+#include <helpers/RadioFailIndicator.h>
 #include "KissModem.h"
 
 #if defined(NRF52_PLATFORM)
@@ -30,7 +31,7 @@ static uint32_t next_noise_floor_calib_ms = 0;
 static uint32_t next_agc_reset_ms = 0;
 
 void halt() {
-  while (1) ;
+  haltWithRadioFailure();
 }
 
 void loadOrCreateIdentity() {

diff --git a/examples/simple_repeater/main.cpp b/examples/simple_repeater/main.cpp
@@ -2,6 +2,7 @@
 #include <Mesh.h>
 
 #include "MyMesh.h"
+#include <helpers/RadioFailIndicator.h>
 
 #ifdef DISPLAY_CLASS
   #include "UITask.h"
@@ -19,7 +20,7 @@ SimpleMeshTables tables;
 MyMesh the_mesh(board, radio_driver, *new ArduinoMillis(), fast_rng, rtc_clock, tables);
 
 void halt() {
-  while (1) ;
+  haltWithRadioFailure();
 }
 
 static char command[160];
@@ -52,16 +53,20 @@ void setup() {
 #endif
 
 #ifdef DISPLAY_CLASS
-  if (display.begin()) {
-    display.startFrame();
-    display.setCursor(0, 0);
-    display.print("Please wait...");
-    display.endFrame();
+  DisplayDriver* disp = display.begin() ? &display : NULL;
+  if (disp != NULL) {
+    disp->startFrame();
+    disp->setCursor(0, 0);
+    disp->print("Please wait...");
+    disp->endFrame();
   }
 #endif
 
   if (!radio_init()) {
     MESH_DEBUG_PRINTLN("Radio init failed!");
+  #ifdef DISPLAY_CLASS
+    showRadioErrorOnDisplay(disp);
+  #endif
     halt();
   }
 

diff --git a/examples/simple_room_server/main.cpp b/examples/simple_room_server/main.cpp
@@ -2,6 +2,7 @@
 #include <Mesh.h>
 
 #include "MyMesh.h"
+#include <helpers/RadioFailIndicator.h>
 
 #ifdef ETHERNET_ENABLED
   #define ETHERNET_CLI_BANNER "MeshCore Room Server CLI"
@@ -18,7 +19,7 @@ SimpleMeshTables tables;
 MyMesh the_mesh(board, radio_driver, *new ArduinoMillis(), fast_rng, rtc_clock, tables);
 
 void halt() {
-  while (1) ;
+  haltWithRadioFailure();
 }
 
 static char command[MAX_POST_TEXT_LEN+1];
@@ -37,15 +38,21 @@ void setup() {
 #endif
 
 #ifdef DISPLAY_CLASS
-  if (display.begin()) {
-    display.startFrame();
-    display.setCursor(0, 0);
-    display.print("Please wait...");
-    display.endFrame();
+  DisplayDriver* disp = display.begin() ? &display : NULL;
+  if (disp != NULL) {
+    disp->startFrame();
+    disp->setCursor(0, 0);
+    disp->print("Please wait...");
+    disp->endFrame();
   }
 #endif
 
-  if (!radio_init()) { halt(); }
+  if (!radio_init()) {
+  #ifdef DISPLAY_CLASS
+    showRadioErrorOnDisplay(disp);
+  #endif
+    halt();
+  }
 
   fast_rng.begin(radio_driver.getRngSeed());
 

diff --git a/examples/simple_secure_chat/main.cpp b/examples/simple_secure_chat/main.cpp
@@ -15,6 +15,7 @@
 #include <helpers/IdentityStore.h>
 #include <RTClib.h>
 #include <target.h>
+#include <helpers/RadioFailIndicator.h>
 
 /* ---------------------------------- CONFIGURATION ------------------------------------- */
 
@@ -552,7 +553,7 @@ SimpleMeshTables tables;
 MyMesh the_mesh(radio_driver, fast_rng, rtc_clock, tables);
 
 void halt() {
-  while (1) ;
+  haltWithRadioFailure();
 }
 
 void setup() {

diff --git a/examples/simple_sensor/main.cpp b/examples/simple_sensor/main.cpp
@@ -1,4 +1,5 @@
 #include "SensorMesh.h"
+#include <helpers/RadioFailIndicator.h>
 
 #ifdef DISPLAY_CLASS
   #include "UITask.h"
@@ -47,7 +48,7 @@ SimpleMeshTables tables;
 MyMesh the_mesh(board, radio_driver, *new ArduinoMillis(), fast_rng, rtc_clock, tables);
 
 void halt() {
-  while (1) ;
+  haltWithRadioFailure();
 }
 
 static char command[160];
@@ -63,14 +64,20 @@ void setup() {
 #endif
 
 #ifdef DISPLAY_CLASS
-  if (display.begin()) {
-    display.startFrame();
-    display.print("Please wait...");
-    display.endFrame();
+  DisplayDriver* disp = display.begin() ? &display : NULL;
+  if (disp != NULL) {
+    disp->startFrame();
+    disp->print("Please wait...");
+    disp->endFrame();
   }
 #endif
 
-  if (!radio_init()) { halt(); }
+  if (!radio_init()) {
+  #ifdef DISPLAY_CLASS
+    showRadioErrorOnDisplay(disp);
+  #endif
+    halt();
+  }
 
   fast_rng.begin(radio_driver.getRngSeed());
 

diff --git a/src/helpers/RadioFailIndicator.h b/src/helpers/RadioFailIndicator.h
@@ -0,0 +1,53 @@
+#pragma once
+
+#include <Arduino.h>
+
+#ifdef DISPLAY_CLASS
+#include <helpers/ui/DisplayDriver.h>
+
+static inline void showRadioErrorOnDisplay(DisplayDriver* disp) {
+  if (disp == NULL) return;
+  disp->startFrame();
+#ifdef ST7789
+  disp->setTextSize(2);
+#endif
+  disp->drawTextCentered(disp->width() / 2, 28, "Radio Error");
+  disp->endFrame();
+}
+#endif
+
+#if defined(LED_PIN) && (LED_PIN >= 0) && (LED_PIN != 0xFF)
+  #define _RADIO_FAIL_LED_PIN LED_PIN
+#elif defined(LED_BUILTIN) && (LED_BUILTIN >= 0) && (LED_BUILTIN != 0xFF)
+  #define _RADIO_FAIL_LED_PIN LED_BUILTIN
+#endif
+
+static inline void haltWithRadioFailure() {
+#if defined(_RADIO_FAIL_LED_PIN) && defined(LED_STATE_ON)
+  pinMode(_RADIO_FAIL_LED_PIN, OUTPUT);
+  const uint16_t UNIT_MS = 300;
+  const uint16_t DASH_MS = UNIT_MS * 3;
+  const uint16_t LETTER_PAUSE_MS = UNIT_MS * 2;
+  const uint16_t WORD_PAUSE_MS = UNIT_MS * 4;
+
+  while (true) {
+    for (uint8_t letter = 0; letter < 3; letter++) {
+      uint16_t onMs = (letter == 1) ? DASH_MS : UNIT_MS;
+      for (uint8_t symbol = 0; symbol < 3; symbol++) {
+        digitalWrite(_RADIO_FAIL_LED_PIN, LED_STATE_ON);
+        delay(onMs);
+        digitalWrite(_RADIO_FAIL_LED_PIN, !LED_STATE_ON);
+        delay(UNIT_MS);
+      }
+      delay(LETTER_PAUSE_MS);
+    }
+    delay(WORD_PAUSE_MS);
+  }
+#else
+  while (1) ;
+#endif
+}
+
+#ifdef _RADIO_FAIL_LED_PIN
+#undef _RADIO_FAIL_LED_PIN
+#endif