ps3.h
void ps3ResetGlobals();

ps3.c
void ps3ResetGlobals() {
    // Own Code
    is_active = false;
    ps3_connection_cb = NULL;
    ps3_connection_object_cb = NULL;
    ps3_connection_object = NULL;
    ps3_event_cb = NULL;
    ps3_event_object_cb = NULL;
    ps3_event_object = NULL;
}

Ps3Controller.h
private
void resetGlobals();

Ps3Controller.cpp
void Ps3Controller::resetGlobals() {
    ps3ResetGlobals();
}

in -> Ps3Controller::begin
this->resetGlobals();