diff --git a/src/main.cpp b/src/main.cpp
index 622bbc5..08fb08e 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -173,6 +173,11 @@ void callback(char* topic, byte* message, unsigned int length) {
     DynamicJsonDocument json(512);
     deserializeJson(json, messageTemp);
     grid_p = json["value"];
+
+    //add to ringbuffer for testing
+    display_graph_ringbuffer[display_graph_ringbuffer_index] = grid_p;
+    if (display_graph_ringbuffer_index == 100)
+     display_graph_ringbuffer_index = 0;
   }
 
   //Inverter - power