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Netduino Plus 2 Native OneWire Temp Sensor


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#21 M8in

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Posted 05 January 2013 - 05:10 PM

Hi,

 

i would like to say thanks for this piece of code. I was able to get all my DS1820 running in two hours of work. And I would like to call me an newbie... ;-)

 

Also I would like to contibute a modified Main() which iterates trought all DS1820 found on the bus and displays the read temperature:

static string DS1820ID = "";static float sensorTemp = -99;public static void Main(){    while (true)    {	Array owSensors = owBus0.FindAllDevices().ToArray();	foreach (byte[] s in owSensors)	{	    DS1820ID = ""; 	    foreach (byte b in s) {		//Debug.Print( );		DS1820ID += b.ToString() + " ";	    }	    sensorTemp = GetOneWireTempByByteArray(s);	    Debug.Print(DS1820ID + " => " + sensorTemp + "F");	}	Thread.Sleep(1000);    }}

Maybe this is usefull for someone....

 

Best regards from Cologne/Germany,

Martin



#22 Ludostes

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Posted 07 January 2013 - 04:23 PM

Hi,

I don't know why, but I had to change this line, otherwise I was getting only 85 degC (which is the power-on reset value of the temperature register, which is +85C)

 

while (owBus0.ReadByte() == 0) ; //wait while busy

into this


 Thread.Sleep(750);

 

 

 

The Temperature Conversion Time is maximum 750miliseconds (for a DS18B20), See also datasheet link
 
And ofcourse you have to add the following reference (Microsoft.SPOT.Hardware.OneWire)
 


#23 iced98lx

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Posted 07 January 2013 - 07:30 PM

Very cool, thank you all for this. Making my DS18B20 easier to use!



#24 Ludostes

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Posted 07 January 2013 - 11:01 PM

I made this, now I need some Idea to work with multiple sensors (and different types) <_<

Made it in vb.net, C# should be almost same

 

Imports Microsoft.SPOTImports Microsoft.SPOT.HardwareImports SecretLabs.NETMF.HardwareImports SecretLabs.NETMF.Hardware.NetduinoModule OneWireTemperature    'Public MyTempMeter As TemperatureOneWire.OneWireSensor    Sub Main()        ' write your code here        Dim MyTempMeter = New TemperatureOneWire.OneWireSensor        MyTempMeter.Start()        While True            'do something            Thread.Sleep(1000)            Debug.Print("My temp raw : " & MyTempMeter.Raw.ToString)            Debug.Print("My temp now : " & MyTempMeter.NowCelcius.ToString)            Debug.Print("My temp now : " & MyTempMeter.NowFahr.ToString)            Debug.Print("My temp ave : " & MyTempMeter.AveCelcius.ToString)            Debug.Print("My temp ave : " & MyTempMeter.AveFahr.ToString)            Thread.Sleep(9000)        End While    End SubEnd Module#Region "Class, Temperature measuring with a OneWire (DS18B20)"Namespace TemperatureOneWire    Public Class OneWireSensor        '----------------------------------------------------------------------        'DS18B20 Commands        'http://datasheets.maximintegrated.com/en/ds/DS18B20.pdf        '----------------------------------------------------------------------        Private Enum OneWireCommand As Byte            'ROM commands            SearchROM = &HF0        'Search slave devices            ReadRom = &H33          'Read slave on bus (only when 1 device is connected)            MatchRom = &H55         'Address a specific slave device            SkipRom = &HCC          'Address all slave devices            AlarmSearch = &HEC      'Find devices in alarm            'Function commands (DS18B20)            ConvertTemp = &H44     'initiates single temperature conversion            WriteScratchPad = &H4E 'Write Th, Tl and config in temperature slave RAM register (3 bytes)            ReadScratchPad = &HBE  'Read slave register (9 bytes)            CopyScratchPad = &H48  'Copy Th, Tl and Config in EEPROM            RecallE2 = &HB8        'Copy Th, Tl and Config from EEPROM to RAM register            ReadPwrSuplly = &HB4   'Read power externally powered slave devices         End Enum        '----------------------------------------------------------------------        'DS18B20 Constants        '----------------------------------------------------------------------        Const cnstConversionTime As Integer = 750  '12 bit conversion time        Const cnstSleeptime As Integer = 10000     'Sleep this thread        Const UnknownValue As Integer = &HAAA      'Initial value after power up        Const SignBit As Integer = &H800           'First Sign Mask is defined here        Const Resolution As Single = 0.0625        'Bit resolution this sensor        Private TemperatureThread As Thread = Nothing        Private RawData As Integer        Private HisData(7) As Integer        Public Sub New()            Me.TemperatureThread = New Thread(AddressOf ReadTemperatureOneWireSensor)            Me.TemperatureThread.Priority = ThreadPriority.Lowest        End Sub        Public Sub Start()            TemperatureThread.Start()        End Sub        '----------------------------------------------------------------------        'Main routine to read tempurature for a SINGLE!! connected device        'I/O to SDA PIN        '----------------------------------------------------------------------        Private Sub ReadTemperatureOneWireSensor()            Dim TemperaturePort As New OutputPort(Pins.GPIO_PIN_SDA, False)            Dim OneWireBus As New OneWire(TemperaturePort)            Dim Data(8) As Integer            Dim Counter As Integer            Counter = 0            For item As Integer = 0 To 7                HisData(item) = UnknownValue            Next            Try                Do While True                    OneWireBus.TouchReset()                    OneWireBus.WriteByte(OneWireCommand.SkipRom)     'Read single device only                    OneWireBus.WriteByte(OneWireCommand.ConvertTemp) 'Start temperature reading/conversion                    Thread.Sleep(cnstConversionTime)                    OneWireBus.TouchReset()                    OneWireBus.WriteByte(OneWireCommand.SkipRom)        'Read single device only                    OneWireBus.WriteByte(OneWireCommand.ReadScratchPad) 'Command to read register                    For item As Integer = 0 To 8                        Data(item) = OneWireBus.ReadByte()              'Read data from register                    Next                    If (Data(0) = &HFF) And (Data(1) = &HFF) And (Data(2) = &HFF) Then           'No data receieved, or crap                        RawData = UnknownValue                    Else                        RawData = (Data(0) + (Data(1) << 8))                   'Raw Temperature data                        'RawData = &HFE6F                                       'Test value = -25.0625                        If (RawData And SignBit) = SignBit Then                'Negative value (sign bit is high)                            RawData = (RawData Or &HFFFF0000)                  'Convert to Negative integer (32bit)                        End If                    End If                    'Collect data for average calculation (shift data)                    If Counter < 8 Then Counter += 1                    If Counter > 1 Then                        For item As Integer = Counter - 1 To 1 Step -1                            HisData(item) = HisData(item - 1)                                     'shift data                        Next                    End If                    HisData(0) = RawData                    Thread.Sleep(cnstSleeptime - cnstConversionTime)                Loop            Catch ex As Exception            End Try        End Sub        '----------------------------------------------------------------------        'Convert raw data temperature to Deg Celcius        '----------------------------------------------------------------------        Private Function ConvertTemp(myData As Integer) As Single            If myData = UnknownValue Then                Return 999            Else                Return CSng(myData * Resolution)            End If        End Function        '----------------------------------------------------------------------        'Convert raw temperature to Deg Fahrenheit        '----------------------------------------------------------------------        Private Function ConvertToFahr(myData As Single) As Single            If myData = 999 Then                Return 999            Else                Return myData * 9 / 5 + 32            End If        End Function        '----------------------------------------------------------------------        'Calculate Average tempurature from last 8 readings        '----------------------------------------------------------------------        Private Function CalcAve() As Single            Dim cnt As Integer            Dim total As Single            For item As Integer = 0 To 7                If HisData(item) <> UnknownValue Then                    cnt += 1                    total += ConvertTemp(HisData(item))                End If            Next            If cnt > 0 Then                Return (total / cnt)            Else                Return 999            End If        End Function        '----------------------------------------------------------------------        'Callup raw data        '----------------------------------------------------------------------        Public ReadOnly Property Raw As Integer            Get                Return Me.RawData            End Get        End Property        '----------------------------------------------------------------------        'Last known value in deg C        '----------------------------------------------------------------------        Public ReadOnly Property NowCelcius As Single            Get                Return ConvertTemp(Me.RawData)            End Get        End Property        '----------------------------------------------------------------------        'Last known value in deg F        '----------------------------------------------------------------------        Public ReadOnly Property NowFahr As Single            Get                Return ConvertToFahr(ConvertTemp(Me.RawData))            End Get        End Property        '----------------------------------------------------------------------        'Average value in deg C        '----------------------------------------------------------------------        Public ReadOnly Property AveCelcius As Single            Get                Return CalcAve()            End Get        End Property        '----------------------------------------------------------------------        'Average value in deg F        '----------------------------------------------------------------------        Public ReadOnly Property AveFahr As Single            Get                Return ConvertToFahr(CalcAve())            End Get        End Property    End ClassEnd Namespace#End Region


#25 M8in

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Posted 11 January 2013 - 09:08 AM

Hi,

 

i ran into the same problem, but my solution was to provide +5V to PIN3 of the DS18S20. The delay of 750ms may be only needed when using "parasitic power"...

 

I discovered a similar problem when playing around with a serial DIY Board for a PC, running Linux and digitemp. The solution was also to use extra power on PIN3 or the delay of 750ms...

http://www.m8in.de/2...igenbau-sensor/ (sorry, german ;-) )

 

Regards, Martin

 

Hi,

I don't know why, but I had to change this line, otherwise I was getting only 85 degC (which is the power-on reset value of the temperature register, which is +85C)

 

while (owBus0.ReadByte() == 0) ; //wait while busy

into this

 

 Thread.Sleep(750);

 

 

The Temperature Conversion Time is maximum 750miliseconds (for a DS18B20), See also datasheet link
 
And ofcourse you have to add the following reference (Microsoft.SPOT.Hardware.OneWire)
 


#26 OZ8ET

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Posted 11 January 2013 - 04:14 PM

For reference - her is my OneWire Engine using Netduino Plus 2 and native OneWire. (it may not run without modifications as it is part of my home automation controller.).

The engine runs in a loop and maintain 2 tables - one for DS1820 and one for DS2438 as these are the once i use.

All use of the data from the devices, are retrieved from these tables.

 

I have used a similar module on Netduino Plus (ver.1) but with the use of CW2's implementation of OneWire. This requires the special firmware and is only availalbe on NETMF 4.1.

 

using System;using System.Collections;using System.Threading;using Config;using Microsoft.SPOT;using Microsoft.SPOT.Hardware;namespace EPD{	static class owCommands	{		public const byte SkipRom = 0xCC;		public const byte MatchRom = 0x55;		public const byte Convert1820 = 0x44;		public const byte ReadScratchpad = 0xBE;		public const byte CopyScratchpad = 0x48;		public const byte WriteScratchpad = 0x4E;		public const byte RecallMemory = 0xB8;		public const byte ConvertT = 0x44;		public const byte ConvertV = 0xB4;	}	static class OneWireExtension	{		public static bool isOwAddr(string parm)		{			if (parm.Length != 16) return false;			for (int i = 0; i < 16; i++)			{				bool ishex = (((parm[i] >= '0') & (parm[i] <= '9')) | ((parm[i] >= 'A') & (parm[i] <= 'F')) | ((parm[i] >= 'a') & (parm[i] <= 'f')));				if (!ishex) return false;			}			return true;		}		const string hexChar = "0123456789ABCDEF";		public static string AddrString(this byte[] buf)	//	{ 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF } converts to 'FECDAB8967452301'		{			string s = string.Empty;			for (int i = 0; i < buf.Length; i++) s += buf[buf.Length - i - 1].toHex();			return s;		}		public static byte[] AddrBytes(this string s)	//	'0123456789ABCDEF' converts to { 0xEF, 0xCD, 0xAB, 0x89, 0x67, 0x45, 0x23, 0x01 }		{			int j = s.Length;			byte[] b = new byte[(j + 1) >> 1];			for (int i = 0; i < j; i++)			{				int ir = b.Length - (i >> 1) - 1;				int x = hexChar.IndexOf(s.ToUpper()[i]);				b[ir] = ((i & 1) == 0) ? (byte)(x << 4) : (byte)(b[ir] | (byte)x);			}			return b;		}		public static int inList(this ArrayList ar, string addr)		{			for (int i = 0 ; i< ar.Count; i++)				{ if ((ar[i] as byte[]).AddrString() == addr) return i;  }			return -1;		}		public static string getLocation(string addr)		{			//string place = HttpClient.webGet("http://palsbo.net/getLocation.php?addr=" + addr);			//if (place != "") Ini.setValue(addr, place);			//return place == "" ? Ini.getValue(addr, "(undefined)") : place;			return Ini.getValue(addr, "(undefined)");		}	}	class OneWireEngine : IDisposable	{		static OneWire core;		public static bool Pause = false;		private static bool ready = false;		public OneWireEngine(OutputPort _core)		{			core = new OneWire(_core);			ds1820.dev.Clear();			new Thread(Start).Start();			while (!ready) { Thread.Sleep(200); }			Debug.Print("OneWire Started");		}		public void Dispose() { GC.SuppressFinalize(this); }		public static void Start()		{			while (true)			{				core.TouchReset();				core.TouchByte(owCommands.SkipRom);				core.TouchByte(owCommands.Convert1820);				Thread.Sleep(750);				var devs = core.FindAllDevices();				lock (ds1820.dev) foreach (ds1820.Device d in ds1820.dev) { if (devs.inList(d.Addr) < 0) ds1820.dev.Remove(d); }				lock (ds2438.dev) foreach (ds2438.Device d in ds2438.dev) { if (devs.inList(d.Addr) < 0) ds2438.dev.Remove(d); }				foreach (byte[] _Rom in devs)				{					string addr = _Rom.AddrString();					if (addr.Substring(14) == "10")					{						double Temp = get1820(_Rom);						int index = ds1820.inList(addr);						if (index < 0)						{							string Place = OneWireExtension.getLocation(addr);							ds1820.dev.Add(new ds1820.Device(addr, Temp, Place));						}						else						{							ds1820.setTemp(index, Temp);						}					}					if (addr.Substring(14) == "26")					{						double Temp = 0.0;						double Current = 0.0;						double Volt = 0.0;						int index = ds2438.inList(addr);						if (index < 0)						{							init2438(_Rom);							get2438(_Rom, ref Temp, ref Current, ref Volt);							string Place = OneWireExtension.getLocation(addr);							ds2438.dev.Add(new ds2438.Device(addr, Temp, Current, Volt, Place));						}						else						{							get2438(_Rom, ref Temp, ref Current, ref Volt);							ds2438.setData(index, Temp, Current, Volt);						}					}					ready = true;					Thread.Sleep(2000);				}			}		}		public static void WriteBytes(byte[] data)		{			foreach (byte B in data) { core.TouchByte(B); }		}		public static void ReadBytes(byte[] buf)		{			for (var i = 0; i < buf.Length; i++) buf[i] = (byte)(core.ReadByte());		}		public static void Match(byte[] addr)		{			core.TouchReset();			core.TouchByte(owCommands.MatchRom); //match rom			WriteBytes(addr);		}		private static double get1820(byte[] _Rom)		{			Match(_Rom);			core.WriteByte(owCommands.ReadScratchpad);			byte[] buf = { 255, 255, 255, 255, 255, 255, 255, 255, 255 };			ReadBytes(buf);			return (float)((short)((buf[1] << 8) | buf[0]) >> 1) + (float)(buf[7] - buf[6]) / (float)buf[7] - .25;		}		private static void init2438(byte[] _Rom)		{			const byte IAD = 0x01;			const byte CA = 0x02;			const byte EE = 0x04;			//const byte AD = 0x08;			const byte Page0 = 0x00;			const byte Ctrl = IAD | CA | EE;			var buf = new byte[9];			Match(_Rom);			WriteBytes(new byte[] { owCommands.WriteScratchpad, Page0, Ctrl });			Match(_Rom);			WriteBytes(new byte[] { owCommands.ReadScratchpad, 0x00 });			ReadBytes(buf);			Match(_Rom);			WriteBytes(new byte[] { owCommands.CopyScratchpad, 0x00 });			while (core.ReadByte() != 0xFF) { };		}		private static void get2438(byte[] _Rom, ref double Temp, ref double Current, ref double Volt)		{			var buf = new byte[9];			Match(_Rom);			core.WriteByte(owCommands.ConvertT);			while (core.ReadByte() != 0xFF) { };			Thread.Sleep(10);			Match(_Rom);			core.WriteByte(owCommands.ConvertV);			while (core.ReadByte() != 0xFF) { };			Thread.Sleep(10);			Match(_Rom);			WriteBytes(new byte[] { owCommands.RecallMemory, 0x00 });			Match(_Rom);			WriteBytes(new byte[] { owCommands.ReadScratchpad, 0x00 });			ReadBytes(buf);			Temp = (double)((buf[2] << 8) + (buf[1])) / 256;			Volt = (double)((buf[4] << 8) + (buf[3])) - 224; // / 100;			//Volt = Volt / 1.75672;			Current = (double)((Int16)(buf[6] << 8) | (Int16)buf[5]);		}	}	class ds1820	{		public class Device		{			public string Addr { get; set; }			public string Place { get; set; }			public double Temp { get; set; }			public Device(string addr, double temp, string place = null)			{				Addr = addr;				Temp = temp;				if (place == null) Place = Ini.getValue(Addr, "(undefined)");				else Place = place;			}		}		public static int inList(string addr)		{			for (int i = 0; i< dev.Count; i++) { if ((dev[i] as Device).Addr == addr) return i; }			return -1;		}		public static string Addr(int i) { return (dev[i] as Device).Addr; }		public static string Place(int i) { return (dev[i] as Device).Place; }		public static void Place(int i, string Place) { (dev[i] as Device).Place = Place; }		public static double Temp(int i) { return (dev[i] as Device).Temp; }		public static void setTemp(int index, double Temp) { (dev[index] as Device).Temp = Temp; }		public static ArrayList dev = new ArrayList();		public static int Count { get { return dev.Count; } }		public class InUse		{			static string _InUse;			public static int Index			{				get				{					for (int i = 0; i < dev.Count; i++) { if (Addr(i) == _InUse) return i; }					if (dev.Count > 0) return 0; else return -1;				}			}			public static string Addr			{				get { return Index < 0 ? "" : Addr(Index); }				set				{					_InUse = value.ToUpper();					Ini.setValue("DS1820inUse", _InUse);				}			}		}	}	class ds2438	{		public class Device		{			public string Addr { get; set; }			public string Place { get; set; }			public double Temp { get; set; }			public double Volt { get; set; }			public double Current { get; set; }			public Device(string addr, double temp, double current, double volt, string place = null)			{				Addr = addr;				Temp = temp;				Current = current;				Volt = volt;				if (place == null) Place = Ini.getValue(Addr, "(undefined)");				else Place = place;			}		}		public static int inList(string addr)		{			for (int i = 0; i<dev.Count; i++) { if ((dev[i] as Device).Addr == addr) return i; }			return -1;		}		public static ArrayList dev = new ArrayList();		public static int Count { get { return dev.Count; } }		public static string Addr(int i) { return (dev[i] as Device).Addr; }		public static string Place(int i) { return (dev[i] as Device).Place; }		public static void Place(int i, string Place) { (dev[i] as Device).Place = Place; }		public static double Temp(int i) { return (dev[i] as Device).Temp; }		public static double Current(int i) { return (dev[i] as Device).Current; }		public static double Volt(int i) { return (dev[i] as Device).Volt; }		public static void setData(int index, double Temp, double Current, double Volt) { 			(dev[index] as Device).Temp = Temp; 			(dev[index] as Device).Current = Current; 			(dev[index] as Device).Volt = Volt;		}		public class InUse		{			static string _InUse;			public static int Index			{				get				{					for (int i = 0; i < dev.Count; i++) { if (Addr(i) == _InUse) return i; }					if (dev.Count > 0) return 0; else return -1;				}			}			public static string Addr			{				get { return Index < 0 ? "" : Addr(Index); }				set				{					_InUse = value.ToUpper();					Ini.setValue("DS2438inUse", _InUse);				}			}		}	}}

(this code block display needs to be fixed!!!)

 



#27 Tal Tikotzki

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Posted 20 January 2013 - 02:29 PM

Oh my, I didn't even notice that. In ReadTemps_Delegate, you're creating a timer. Which will then get garbage collected at some point, since its scope is limited to the function. Try creating a static variable for the timer outside of that function, and then instantiate it in that function instead. Chris

Hey Chris,

  Why would should I instantiate a timer inside the thread delegate and not at the main thread?

  Doesn't the timer callback returns in a worker thread every time? 

 

Tal






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