#ifndef GUY_H
#define GUY_H

#include <QGraphicsItem>
#include <QTimer>
#include <QObject>

class Guy : public QGraphicsItem
{
public:
    Guy(int x, int y);

    void timerStart();

public slots:
    void onTimeOutTimer();

    [...]

    QTimer *timer;
}

#endif // GUY_H

#include "guy.h"

#include <QTimer>
#include <QObject>

#include <stdio.h>
#include <iostream>

Guy::Guy(int x, int y)
{
    timer = new QTimer();
}

void Guy::timerStart()
{
    QObject::connect(timer, SIGNAL(timeout()), this, SLOT(onTimeOutTimer()));
    this->timer->setInterval(1000);
    this->timer->start();
    std::cout << "starting timer" << std::endl;
}

void Guy::onTimeOutTimer()
{
    std::cout << "check" << std::endl;
}

No matching function for call to 'QObject::connect(QTimer*&, const char*, Guy* const, const char*)'