diff --git a/simulation/src/de/c3ma/ollo/mockup/ESP8266Ws2812.java b/simulation/src/de/c3ma/ollo/mockup/ESP8266Ws2812.java
index 50b55ec..a8f4110 100644
--- a/simulation/src/de/c3ma/ollo/mockup/ESP8266Ws2812.java
+++ b/simulation/src/de/c3ma/ollo/mockup/ESP8266Ws2812.java
@@ -131,11 +131,16 @@ public class ESP8266Ws2812 extends TwoArgFunction {
             	 final LuaString color = varargs.arg(2).checkstring();
  				final int length = color.rawlen();
  				if (length == 3) {
- 					final byte[] array = color.m_bytes;
- 					int r = array[0]+(Byte.MIN_VALUE*-1);
- 					int b = array[1]+(Byte.MIN_VALUE*-1);
- 					int g = array[2]+(Byte.MIN_VALUE*-1);
- 					ESP8266Ws2812.layout.fillLEDs(r, g, b);
+ 					SwingUtilities.invokeLater(new Runnable() {
+						@Override
+						public void run() {
+		 					final byte[] array = color.m_bytes;
+		 					int r = array[0]+(Byte.MIN_VALUE*-1);
+		 					int b = array[1]+(Byte.MIN_VALUE*-1);
+		 					int g = array[2]+(Byte.MIN_VALUE*-1);
+		 					ESP8266Ws2812.layout.fillLEDs(r, g, b);
+						} 
+					});
  				}
  				return LuaValue.valueOf(true);
             } else {
@@ -153,11 +158,16 @@ public class ESP8266Ws2812 extends TwoArgFunction {
                 final LuaString color = varargs.arg(2).checkstring();
 				final int length = color.rawlen();
 				if (length == 3) {
-					final byte[] array = color.m_bytes;
-					int r = array[0]+(Byte.MIN_VALUE*-1);
-					int b = array[1]+(Byte.MIN_VALUE*-1);
-					int g = array[2]+(Byte.MIN_VALUE*-1);
-					ESP8266Ws2812.layout.updateLED(index, r, g, b);
+					SwingUtilities.invokeLater(new Runnable() {
+						@Override
+						public void run() {
+							final byte[] array = color.m_bytes;
+							int r = array[0]+(Byte.MIN_VALUE*-1);
+							int b = array[1]+(Byte.MIN_VALUE*-1);
+							int g = array[2]+(Byte.MIN_VALUE*-1);
+							ESP8266Ws2812.layout.updateLED(index, r, g, b);
+						}
+					});
 				}
                 
                 return LuaValue.valueOf(true);