Added output of heap to check memory leakage.

src/Display.cpp

@@ -4,6 +4,9 @@
 #include <MD_MAX72xx.h>
 #include <SPI.h>
 #include "MD_RobotEyes.h"
+extern "C" {
+#include "user_interface.h"
+}
 
 #define DISPLAY_CLK_PIN D5
 #define DISPLAY_DATA_PIN D7
@@ -181,6 +184,7 @@ void Display::loop() {
 }
 
 void Display::reInitializeDisplay() {
+  uint32_t free = system_get_free_heap_size();
   #define REINIT_AFTER_ms 5000
   #define AVOID_REINIT_BEFORE_AND_AFTER_FULLMINUTE_FOR_s 3
 
@@ -190,7 +194,7 @@ void Display::reInitializeDisplay() {
       && currentTime->getSeconds() < 60 - AVOID_REINIT_BEFORE_AND_AFTER_FULLMINUTE_FOR_s
       && currentTime->getSeconds() > AVOID_REINIT_BEFORE_AND_AFTER_FULLMINUTE_FOR_s) {
     P.begin();
-    Serial.println("reinit display");
+    Serial.print("reinit display, free="); Serial.println(free);
     last_reinit_ts = millis();
   }
 }