diff --git a/OpenMQTTGateway.ino b/OpenMQTTGateway.ino
index d13861a..0ec5570 100644
--- a/OpenMQTTGateway.ino
+++ b/OpenMQTTGateway.ino
@@ -110,13 +110,14 @@
   #include "config_GPIOInput.h"
 #endif
 // array to store previous received RFs, IRs codes and their timestamps
-#if defined(ESP8266) || defined(ESP32)
-#define MQTT_MAX_PACKET_SIZE 1024
-#define array_size 12
-unsigned long ReceivedSignal[array_size][2] ={{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0}};
-#else
-#define array_size 4
-unsigned long ReceivedSignal[array_size][2] ={{0,0},{0,0},{0,0},{0,0}};
+#if defined(ESP8266) || defined(ESP32) || defined(__AVR_ATmega2560__) || defined(__AVR_ATmega1280__)
+  #define MQTT_MAX_PACKET_SIZE 1024
+  #define array_size 12
+  unsigned long ReceivedSignal[array_size][2] ={{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0}};
+#else // boards with smaller memory
+  #define MQTT_MAX_PACKET_SIZE 256
+  #define array_size 4
+  unsigned long ReceivedSignal[array_size][2] ={{0,0},{0,0},{0,0},{0,0}};
 #endif
 /*------------------------------------------------------------------------*/