nickNetduino

Ok folks, I've spent a day hacking this together but it appears to finally work. However, I was hoping some of the more experienced coders here might be able to critique this code to see what I may have not done very elegantly. Basically what the code should do is check the temperatures of 2 sensors ( DS18B20 ) every 10 seconds and store it in a global variable that may be read by a web client or logged. Thanks much in advance.

Sample Debug Output:

11/11/2012 19:03:25 Temp Inside: 67.8 Temp Outside: 44.4
11/11/2012 19:03:35 Temp Inside: 67.9 Temp Outside: 44.4
11/11/2012 19:03:45 Temp Inside: 67.9 Temp Outside: 44.5
11/11/2012 19:03:55 Temp Inside: 67.9 Temp Outside: 44.5
11/11/2012 19:04:05 Temp Inside: 67.9 Temp Outside: 44.5

public class Program
    {
        static OutputPort led = new OutputPort(Pins.ONBOARD_LED, false);
        static OutputPort owPort0 = new OutputPort(Pins.GPIO_PIN_D0, false);
        static OneWire owBus0 = new OneWire(owPort0);

        static byte[] owSensor1 = new byte[8] { 40, 168, 176, 219, 3, 0, 0, 221 }; //sensor 1 inside building
        static byte[] owSensor2 = new byte[8] { 40, 172, 164, 219, 3, 0, 0, 98 }; //sensor 2 outside building

        static float owSensor1Temp = -99;
        static float owSensor2Temp = -99;
        static DateTime tempReadingTimestamp = DateTime.Now;

        public static void Main()
        {
            //set ip and get time from a time server
            Microsoft.SPOT.Net.NetworkInformation.NetworkInterface ni = Microsoft.SPOT.Net.NetworkInformation.NetworkInterface.GetAllNetworkInterfaces()[0];
            ni.EnableStaticIP("10.10.40.80", "255.255.255.0", "10.10.40.1");
            SetTime();

            //create a web server
            WebServer server = new WebServer(80);
            server.CommandReceived += new WebServer.CommandReceivedHandler(server_CommandReceived);
            server.AllowedCommands.Add(new WebCommand("getTemp", 1));
            server.Start();

            //thread to blink the led every 250ms
            Thread ledBlinkThread = new Thread(BlinkLed_Delegate);
            ledBlinkThread.Start();

            //thread to read temps every 10 seconds
            Thread readTempsThread = new Thread(ReadTemps_Delegate);
            readTempsThread.Start();
            
            //loop
            while (true)
            {
                //stay alive
            }
        }

        private static void ReadTemps_Delegate()
        {
            Timer readTempsTimer = new Timer(new TimerCallback(ReadTemps_Tick), null, 0, 10000);
        }

        private static void ReadTemps_Tick(Object obj)
        {
            tempReadingTimestamp = DateTime.Now;
            owSensor1Temp = GetOneWireTempByByteArray(owSensor1);
            owSensor2Temp = GetOneWireTempByByteArray(owSensor2);

            string debugString = tempReadingTimestamp.ToString();
            debugString += " Temp Inside: " + owSensor1Temp.ToString("N1");
            debugString += " Temp Outside: " + owSensor2Temp.ToString("N1");
            Debug.Print(debugString);
        }

        static float GetOneWireTempByByteArray(byte[] sensor)
        {
            float TemperatureC = 0;
            int tempLow = 0;
            int tempHigh = 0;
            int temptemp;

            owBus0.TouchReset(); //reset
            owBus0.TouchByte(0x55); //match rom
            foreach (byte b in sensor) //send the whole byte array
            {
                owBus0.TouchByte(B);
            }
            owBus0.TouchByte(0x44); //start temp conversion
            while (owBus0.ReadByte() == 0) ; //wait while busy
            owBus0.TouchReset(); //reset
            owBus0.TouchByte(0x55); //match rom
            foreach (byte b in sensor) //send the whole byte array
            {
                owBus0.TouchByte(B);
            }
            owBus0.TouchByte(0xBE); //read scratchpad
            tempLow = owBus0.ReadByte(); //LSB
            tempHigh = owBus0.ReadByte(); //MSB
            temptemp = (((int)(tempHigh) << 8) | tempLow);
            TemperatureC = temptemp * 0.0625f;

            // temperature is negative if sign bit set
            if (!((tempHigh & 0x80) == 0))
            {
                short t = 0;
                float result = 0f;

                // construct complete temp value
                t = (short)((tempHigh << 8) + tempLow);

                // if negative, take two's complement to get absolute value
                t = (short)-t;

                // get integer part if any
                result = (float)(t >> 8);

                // remove zero bits and add fractional part if any
                result += ((t >> 3) & 0x1f) * 0.03125f;

                // return value with correct sign
                TemperatureC = -result;
            }
            return (float)((TemperatureC * 9.00 / 5.00) + 32.00);
        }

  //left out some non essential code
}