private void polacz_Click(object sender, EventArgs e)
        {
            if (!serialPort1.IsOpen)
            {
                serialPort1.PortName = "COM3";
                serialPort1.BaudRate = 9600;
                serialPort1.DtrEnable = true;
                serialPort1.Open();

                textBox1.Text = "Otwarto port " + serialPort1.PortName;
            }
        }

        private void rozlacz_Click(object sender, EventArgs e)
        {
            serialPort1.Close();
            textBox1.Text = "Zamknieto port";

        }

        private void serialPort1_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)
        {
            dane1 = serialPort1.ReadExisting();
            this.Invoke(new EventHandler(pokazdane));
        }

        private void pokazdane(object sender, EventArgs e)
        {
            textBox2.Text = dane1;
        }