WASD Control for R/C Car using Arduino

/* Author: Adam K Dean (imdsm.blogspot.org) */
using System;
using System.Windows.Forms;
using System.IO.Ports;
using System.Threading;

namespace SerialRC_Car
{
    public enum ThrottleState { Forward, Reverse, None };
    public enum TurnState { Left, Right, None };

    public partial class frmMain : Form
    {
        private Thread readThread;
        private SerialPort _serialPort;
        private bool _continue;

        private ThrottleState throttleState = ThrottleState.None;
        private TurnState turnState = TurnState.None;


        public frmMain()
        {
            InitializeComponent();
            Toggle(false);
        }

        private void frmMain_Load(object sender, EventArgs e)
        {
            comboPort.Items.AddRange(SerialPort.GetPortNames());
        }

        private void btnLoad_Click(object sender, EventArgs e)
        {
            try
            {
                _serialPort = new SerialPort();

                // Allow the user to set the appropriate properties.
                _serialPort.PortName = comboPort.SelectedItem.ToString();
                _serialPort.BaudRate = 9600;
                _serialPort.Parity = Parity.None;
                _serialPort.Handshake = Handshake.None;

                // Set the read/write timeouts
                _serialPort.ReadTimeout = 500;
                _serialPort.WriteTimeout = 500;

                readThread = new Thread(Read);
                _serialPort.Open();
                _continue = true;
                readThread.Start();

                Toggle(true);
            }
            catch (Exception ex)
            {
                WriteLogText("Exception: {0}", ex.Message);
            }
        }

        private void btnStop_Click(object sender, EventArgs e)
        {
            Toggle(false);

            _continue = false;
            readThread.Join();
            _serialPort.Close();
        }

        private void frmMain_KeyDown(object sender, KeyEventArgs e)
        {
            if (e.KeyCode == Keys.W) btnW_MouseDown(this, null);
            else if (e.KeyCode == Keys.S) btnS_MouseDown(this, null);
            else if (e.KeyCode == Keys.A) btnA_MouseDown(this, null);
            else if (e.KeyCode == Keys.D) btnD_MouseDown(this, null);
        }

        private void frmMain_KeyUp(object sender, KeyEventArgs e)
        {
            if (e.KeyCode == Keys.W) btnW_MouseUp(this, null);
            else if (e.KeyCode == Keys.S) btnS_MouseUp(this, null);
            else if (e.KeyCode == Keys.A) btnA_MouseUp(this, null);
            else if (e.KeyCode == Keys.D) btnD_MouseUp(this, null);
        }

        #region Throttle Control
            #region Forward - W
            private void btnW_MouseDown(object sender, MouseEventArgs e)
            {
                if (throttleState != ThrottleState.Forward)
                {
                    if (throttleState == ThrottleState.Reverse) btnS_MouseUp(this, null);
                    throttleState = ThrottleState.Forward;
                    _serialPort.Write("blink;w1;");
                }
            }

            private void btnW_MouseUp(object sender, MouseEventArgs e)
            {
                throttleState = ThrottleState.None;
                _serialPort.Write("blink;w0;");
            }
            #endregion

            #region Reverse - S
            private void btnS_MouseDown(object sender, MouseEventArgs e)
            {
                if (throttleState != ThrottleState.Reverse)
                {
                    if (throttleState == ThrottleState.Forward) btnW_MouseUp(this, null);
                    throttleState = ThrottleState.Reverse;
                    _serialPort.Write("blink;s1;");
                }
            }

            private void btnS_MouseUp(object sender, MouseEventArgs e)
            {
                throttleState = ThrottleState.None;
                _serialPort.Write("blink;s0;");
            }
            #endregion
        #endregion

        #region Steering Control
            #region Left - A
            private void btnA_MouseDown(object sender, MouseEventArgs e)
            {
                if (turnState != TurnState.Left)
                {
                    if (turnState == TurnState.Right) btnD_MouseUp(this, null);
                    turnState = TurnState.Left;
                    _serialPort.Write("blink;a1;");
                }
            }

            private void btnA_MouseUp(object sender, MouseEventArgs e)
            {
                turnState = TurnState.None;
                _serialPort.Write("blink;a0;");
            }
            #endregion

            #region Right - D
            private void btnD_MouseDown(object sender, MouseEventArgs e)
            {
                if (turnState != TurnState.Right)
                {
                    if (turnState == TurnState.Left) btnA_MouseUp(this, null);
                    turnState = TurnState.Right;
                    _serialPort.Write("blink;d1;");
                }
            }

            private void btnD_MouseUp(object sender, MouseEventArgs e)
            {
                turnState = TurnState.None;
                _serialPort.Write("blink;d0;");
            }
            #endregion
        #endregion

        private void WriteLogText(string format, params object[] args)
        {
            WriteLogText(string.Format(format, args));
        }
        private void WriteLogText(string text)
        {
            if (InvokeRequired)
            {
                Action<string> del = new Action<string>(WriteLogText);
                Invoke(del, text);
                return;
            }

            if (txtLog.Text.Length == 0) txtLog.Text = text;
            else txtLog.Text += "\r\n" + text;
            if (txtLog.Text.Length > 5000)
                txtLog.Text = txtLog.Text.Substring(txtLog.Text.Length - 5000);
            txtLog.SelectionStart = txtLog.Text.Length;
            txtLog.ScrollToCaret();
        }

        public void Read()
        {
            while (_continue)
            {
                try
                {
                    string message = _serialPort.ReadLine();
                    WriteLogText("RECV> {0}", message);
                }
                catch (TimeoutException) { }
            }
        }

        private void Toggle(bool enabled)
        {
            comboPort.Enabled = !enabled;
            btnLoad.Enabled = !enabled;
            btnStop.Enabled = enabled;
            btnW.Enabled = enabled;
            btnA.Enabled = enabled;
            btnS.Enabled = enabled;
            btnD.Enabled = enabled;
        }
    }
}

/* Author: Adam K Dean (imdsm.blogspot.org) */

/* Control for RC Car
 * Adam K Dean 2011
 * adamkdean.co.uk
 */

int led = 13;

int fwd = 11;
int rev = 10;
int left = 9;
int right = 8;

void setup()
{
  pinMode(led, OUTPUT);

  pinMode(fwd, OUTPUT);
  pinMode(rev, OUTPUT);
  pinMode(left, OUTPUT);
  pinMode(right, OUTPUT);

  Serial.begin(9600);
  Serial.println("Started..");
}

void loop()
{
  String line = readLineIfAvailable();

  if (line.length() > 0 ) Serial.println(line);

  if (line == "blink")
  {
    digitalWrite(led, HIGH);
    delay(10);
    digitalWrite(led, LOW);
  }

  // forward - w
  if (line == "w1")
  {
    digitalWrite(fwd, HIGH);
  }
  else if (line == "w0")
  {
    digitalWrite(fwd, LOW);
  }

  // reverse - s
  if (line == "s1")
  {
    digitalWrite(rev, HIGH);
  }
  else if (line == "s0")
  {
    digitalWrite(rev, LOW);
  }

  // left - a
  if (line == "a1")
  {
    digitalWrite(left, HIGH);
  }
  else if (line == "a0")
  {
    digitalWrite(left, LOW);
  }

  // right - d
  if (line == "d1")
  {
    digitalWrite(right, HIGH);
  }
  else if (line == "d0")
  {
    digitalWrite(right, LOW);
  }  

  delay(10);
}

String readLineIfAvailable()
{
  String readstr;

  while(Serial.available())
  {
    if (Serial.available() > 0)
    {
      char c = Serial.read();

      if (c == ';') return readstr;
      else readstr += c;
    }
  }
}