Use the serial connection to debug your sketch

SerialDebug.h

#ifndef __SERIAL_DEBUG
#define __SERIAL_DEBUG

    #if SERIAL_DEBUG

        #ifndef SERIAL_DEBUG_SEPARATOR
            #define SERIAL_DEBUG_SEPARATOR " | "
        #endif

        #define DEBUG_0()                   Serial.println("### SerialDebug ###")
        #define DEBUG_1(A)                  Serial.println(A)
        #define DEBUG_2(A,B)                Serial.print(A);Serial.print(SERIAL_DEBUG_SEPARATOR);\
                                            Serial.println(B)
        #define DEBUG_3(A,B,C)              Serial.print(A);Serial.print(SERIAL_DEBUG_SEPARATOR);\
                                            Serial.print(B);Serial.print(SERIAL_DEBUG_SEPARATOR);\
                                            Serial.println(C)
        #define DEBUG_4(A,B,C,D)            Serial.print(A);Serial.print(SERIAL_DEBUG_SEPARATOR);\
                                            Serial.print(B);Serial.print(SERIAL_DEBUG_SEPARATOR);\
                                            Serial.print(C);Serial.print(SERIAL_DEBUG_SEPARATOR);\
                                            Serial.println(D)
        #define DEBUG_5(A,B,C,D,E)          Serial.print(A);Serial.print(SERIAL_DEBUG_SEPARATOR);\
                                            Serial.print(B);Serial.print(SERIAL_DEBUG_SEPARATOR);\
                                            Serial.print(C);Serial.print(SERIAL_DEBUG_SEPARATOR);\
                                            Serial.print(D);Serial.print(SERIAL_DEBUG_SEPARATOR);\
                                            Serial.println(E)
        #define DEBUG_6(A,B,C,D,E,F)        Serial.print(A);Serial.print(SERIAL_DEBUG_SEPARATOR);\
                                            Serial.print(B);Serial.print(SERIAL_DEBUG_SEPARATOR);\
                                            Serial.print(C);Serial.print(SERIAL_DEBUG_SEPARATOR);\
                                            Serial.print(D);Serial.print(SERIAL_DEBUG_SEPARATOR);\
                                            Serial.print(E);Serial.print(SERIAL_DEBUG_SEPARATOR);\
                                            Serial.println(F)
        #define DEBUG_7(A,B,C,D,E,F,G)      Serial.print(A);Serial.print(SERIAL_DEBUG_SEPARATOR);\
                                            Serial.print(B);Serial.print(SERIAL_DEBUG_SEPARATOR);\
                                            Serial.print(C);Serial.print(SERIAL_DEBUG_SEPARATOR);\
                                            Serial.print(D);Serial.print(SERIAL_DEBUG_SEPARATOR);\
                                            Serial.print(E);Serial.print(SERIAL_DEBUG_SEPARATOR);\
                                            Serial.print(F);Serial.print(SERIAL_DEBUG_SEPARATOR);\
                                            Serial.println(G)
        #define DEBUG_8(A,B,C,D,E,F,G,H)    Serial.print(A);Serial.print(SERIAL_DEBUG_SEPARATOR);\
                                            Serial.print(B);Serial.print(SERIAL_DEBUG_SEPARATOR);\
                                            Serial.print(C);Serial.print(SERIAL_DEBUG_SEPARATOR);\
                                            Serial.print(D);Serial.print(SERIAL_DEBUG_SEPARATOR);\
                                            Serial.print(E);Serial.print(SERIAL_DEBUG_SEPARATOR);\
                                            Serial.print(F);Serial.print(SERIAL_DEBUG_SEPARATOR);\
                                            Serial.print(G);Serial.print(SERIAL_DEBUG_SEPARATOR);\
                                            Serial.println(H)
        #define DEBUG_9(A,B,C,D,E,F,G,H,I)  Serial.print(A);Serial.print(SERIAL_DEBUG_SEPARATOR);\
                                            Serial.print(B);Serial.print(SERIAL_DEBUG_SEPARATOR);\
                                            Serial.print(C);Serial.print(SERIAL_DEBUG_SEPARATOR);\
                                            Serial.print(D);Serial.print(SERIAL_DEBUG_SEPARATOR);\
                                            Serial.print(E);Serial.print(SERIAL_DEBUG_SEPARATOR);\
                                            Serial.print(F);Serial.print(SERIAL_DEBUG_SEPARATOR);\
                                            Serial.print(G);Serial.print(SERIAL_DEBUG_SEPARATOR);\
                                            Serial.print(H);Serial.print(SERIAL_DEBUG_SEPARATOR);\
                                            Serial.println(I)

        #define DEBUG_X(x,A,B,C,D,E,F,G,H,I,MACRO, ...) MACRO

        #define DEBUG(...)                  DEBUG_X(,##__VA_ARGS__,\
                                                DEBUG_9(__VA_ARGS__),\
                                                DEBUG_8(__VA_ARGS__),\
                                                DEBUG_7(__VA_ARGS__),\
                                                DEBUG_6(__VA_ARGS__),\
                                                DEBUG_5(__VA_ARGS__),\
                                                DEBUG_4(__VA_ARGS__),\
                                                DEBUG_3(__VA_ARGS__),\
                                                DEBUG_2(__VA_ARGS__),\
                                                DEBUG_1(__VA_ARGS__),\
                                                DEBUG_0(__VA_ARGS__)\
                                            )

        #define SERIAL_DEBUG_SETUP(SPEED)   Serial.begin(SPEED)
    #else
        #define DEBUG(...)
        #define SERIAL_DEBUG_SETUP(SPEED)
    #endif
#endif