diff --git a/UAV-ControlSystem/src/drivers/arduino_com.c b/UAV-ControlSystem/src/drivers/arduino_com.c
index 8e1394d..594ff57 100644
--- a/UAV-ControlSystem/src/drivers/arduino_com.c
+++ b/UAV-ControlSystem/src/drivers/arduino_com.c
@@ -11,32 +11,40 @@
 #include "string.h"
 #include "stm32f4xx_revo.h"
 
+#define COMPASS_PACKET_SIZE 8
+#define GPS_PACKET_SIZE 10
+
+
 usart_dma_profile dmaHandler;
 dma_usart_return raw_dma_data_t;
 
+// enumeration to hold the id:s of the different packages
 enum packet_ids {
 	COMPASS_PACKET_ID 	= 0xA1,
 	GPS_PACKET_ID 		= 0xB1,
 };
 
+// Structure used to hold the data for "data_arr"
 typedef struct arduino_data_t {
 	uint8_t size;	//Size of the data
 	void * dataPtr;	//pointer to the data
 } arduino_data_t ;
 
+// An enumeration of the array positions of the data in the "data_arr"
 enum arduino_data_e {
 	COMPASS_DATA_ID,
 	GPS_DATA_ID,
 	ARDUINO_DATA_COUNT,
 };
 
+// An array to hold the pointers to the different data structures that are used in the rest of the system;
 arduino_data_t data_arr[ARDUINO_DATA_COUNT] = {
 		[COMPASS_DATA_ID] = {
-			.size = 8,
+			.size = COMPASS_PACKET_SIZE,
 			.dataPtr = &compass_data,
 		},
 		[GPS_DATA_ID] = {
-			.size = 10,
+			.size = GPS_PACKET_SIZE,
 			.dataPtr = &gps_data,
 		},
 };