Klassenfunktion kann nicht in den Timer geladen werden

class ReadADCValues {

    public:

        bool is_active;         

        bool error;             

        void init  ();

        void start ();          

        void stopp ();          

        void set_sampling_rate (uint16_t value);  

    private:

        bool check;                     

        void tickerfunction (); 

        uint16_t sampling_rate;

};

void ReadADCValues::init() {

    is_active     = false;             

    error         = false;             

    check         = false;             

    sampling_rate = 100;

}

void ReadADCValues::start() {

    timer.attach(&ReadADCValues::tickerfunction, sampling_rate);

}

void ReadADCValues::stopp() {

    timer.detach();    

}

void ReadADCValues::set_sampling_rate(uint16_t value) {

    sampling_rate = value;

}

void ReadADCValues::tickerfunction() {

    if (check == true) {

        error = true;

    }

    check = true;

    // tu was...

    check = false;    

}

void ReadADCValues::start() {

    timer.attach(&ReadADCValues::tickerfunction, sampling_rate);

}