java animation, making an object change color every 'x' seconds

hi there i was just wondering if someone could help me or give me some advice with timers, the problem i have got is that i need an object to change color every x seconds on click of a button 'flash' and stay a single color on click of a button 'steady' so far i have got my buttons to work i just cant seem to get the object to 'flash'(change color on its own). my code is below and works without problems.

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;


/**
 * Created by joe on 26/03/15.
 */

    class Beacon extends JPanel {
    private boolean lightOn = true;

    private int x = 150;
    private int y = 90;
    private int ballSize = 55;

        public void paintComponent(Graphics g) {
                super.paintComponent(g);
                Graphics2D g2 = (Graphics2D) g;
                if (lightOn){
                    g2.setColor(Color.BLACK);
                    g2.fillRect(172, 140, 12, 30);
                    g2.drawRect(172, 170, 11, 30);
                    g2.fillRect(172, 200, 12, 30);
                    g2.drawRect(172, 230, 11, 30);
                    g2.fillRect(172, 260, 12, 30);
                    g2.drawRect(172, 290, 11, 30);
                    g2.fillRect(172, 320, 12, 30);
                    g2.drawRect(172, 350, 11, 30);
                    g2.setColor(Color.ORANGE);
                    g2.fillOval(x, y, ballSize, ballSize);
                }
            else{
        g2.setColor(Color.BLACK);
        g2.fillRect(172, 140, 12, 30);
        g2.drawRect(172, 170, 11, 30);
        g2.fillRect(172, 200, 12, 30);
        g2.drawRect(172, 230, 11, 30);
        g2.fillRect(172, 260, 12, 30);
        g2.drawRect(172, 290, 11, 30);
        g2.fillRect(172, 320, 12, 30);
        g2.drawRect(172, 350, 11, 30);
        g2.setColor(Color.GRAY);
        g2.fillOval(x, y, ballSize, ballSize);
    }   }
    public void lightOn() { lightOn = true; }
    public void lightOff() { lightOn = false; }
}

    public class BeaconViewer extends JFrame
    {
        JButton Flash = new JButton("Flash");
        JButton Steady = new JButton("Steady");
        JPanel bPanel = new JPanel();
        Beacon bbPanel = new Beacon();



    public BeaconViewer()
    {
        bPanel.add(Flash);
        this.add(bPanel, BorderLayout.SOUTH);
        bPanel.add(Steady);
        this.add(bbPanel, BorderLayout.CENTER);
        Flash.addActionListener(new FlashListener());
        Steady.addActionListener(new SteadyListener());
    }

        class FlashListener implements ActionListener {

            public void actionPerformed(ActionEvent e) {
                bbPanel.lightOff();
                repaint();

            }

        }

        class SteadyListener implements ActionListener {

            public void actionPerformed(ActionEvent a) {
                bbPanel.lightOn();
                repaint();
            }

        }

        public static void main(String[] args) {
        JFrame scFrame = new BeaconViewer();
        scFrame.setTitle("Belish Beacon");
        scFrame.setSize(300, 500);
        scFrame.setDefaultCloseOperation((JFrame.EXIT_ON_CLOSE));
        scFrame.setVisible(true); }}