EmbDev.net

Forum: µC & Digital Electronics Humidity Sensor with DHT11 and PIC16F676


Humidity Sensor with DHT11 and PIC16F676
von Dominic (oepfel)

Attached files:
Rate this post
• ▲ useful
▼ not useful 
Hello Guys

I am trying to develop a humidity sensor with DHT11 for my bathroom. The 
DHT11 Sensor reads the humidity and sends it to the PIC, if the humidity 
is over 75% a LED should light up. If its under 75% the LED is off.

But I have two problems.

First of all I am programming the PIC16F676 with a PICKIT3 clone - and 
when trying to debug my code the following error appears in MPLAB (1) 
Error when trying to debug:
)

_But now to my project:_

If I upload (2)code without error-search), nothing really happens with 
the LED, when the humidity rises. Even if I change line 46 to "if ( 
int_RH > 0 )". This is probably the case because line 46 never happens. 
Thats because result isn't eaqual to 0.

So i tried to find out, where in the function "uint8_t Read_DHT ( 
uint8_t *data )" the problem happens.

And after changing the code to (3) Code with error-search) i found out, 
that the problem is due to the timeout in line 118
1
    uint16_t timeout = 10000;

2
    while ( SENSOR == 1 )

3
    {

4
        if ( --timeout == 0 )

5
        {

6
            return 0x0F;

7
        }

8
    }


*Interesting:*
If I upload the same code to a programming board with the PIC18F45K22 
and add the DHT11 Sensor, everything works as it should. Sadly I am not 
able to use this programming board for my project. Therefore I would 
like to do it with the PIC16F676.

Have you guys any idea, how i can fix this problem?

If you need to know anything about the circuit, I added the schmetic to 
the attachment.


 + I am new to the forum therefore I apologise if I forgot to add 
something you should know.



1) Error when trying to debug:
1
make -f nbproject/Makefile-default.mk SUBPROJECTS= .build-conf

2
make  -f nbproject/Makefile-default.mk dist/default/debug/test.X.debug.elf

3
make[2]: Entering directory 'C:/Users/domin/Desktop/ueK_6/test.X'

4
"C:\Program Files\Microchip\xc8\v2.46\bin\xc8-cc.exe"  -mcpu=16F676 -c  -D__DEBUG=1  -mdebugger=pickit3   -mdfp="C:/Program Files/Microchip/MPLABX/v6.20/packs/Microchip/PIC16Fxxx_DFP/1.6.156/xc8"  -fno-short-double -fno-short-float -fasmfile -maddrqual=ignore -xassembler-with-cpp -mwarn=-2 -Wa,-a -DXPRJ_default=default  -msummary=-psect,-class,+mem,-hex,-file  -ginhx32 -Wl,--data-init -mno-keep-startup -mno-osccal -mno-resetbits -mno-save-resetbits -mno-download -mno-stackcall -mdefault-config-bits   -std=c99 -gdwarf-3 -mstack=compiled:auto:auto     -o build/default/debug/main.p1 main.c 

5
::: advisory: (2100) using the C99 standard library with the selected device may result in larger code and data usage

6
make[2]: Leaving directory 'C:/Users/domin/Desktop/ueK_6/test.X'

7
make[2]: Entering directory 'C:/Users/domin/Desktop/ueK_6/test.X'

8
"C:\Program Files\Microchip\xc8\v2.46\bin\xc8-cc.exe"  -mcpu=16F676 -c  -D__DEBUG=1  -mdebugger=pickit3   -mdfp="C:/Program Files/Microchip/MPLABX/v6.20/packs/Microchip/PIC16Fxxx_DFP/1.6.156/xc8"  -fno-short-double -fno-short-float -fasmfile -maddrqual=ignore -xassembler-with-cpp -mwarn=-2 -Wa,-a -DXPRJ_default=default  -msummary=-psect,-class,+mem,-hex,-file  -ginhx32 -Wl,--data-init -mno-keep-startup -mno-osccal -mno-resetbits -mno-save-resetbits -mno-download -mno-stackcall -mdefault-config-bits   -std=c99 -gdwarf-3 -mstack=compiled:auto:auto     -o build/default/debug/configuration_bits.p1 configuration_bits.c 

9
::: advisory: (2100) using the C99 standard library with the selected device may result in larger code and data usage

10
make[2]: Leaving directory 'C:/Users/domin/Desktop/ueK_6/test.X'

11
make[2]: *** [nbproject/Makefile-default.mk:143: dist/default/debug/test.X.debug.elf] Error 1

12
make[1]: *** [nbproject/Makefile-default.mk:85: .build-conf] Error 2

13
make: *** [nbproject/Makefile-impl.mk:39: .build-impl] Error 2

14
make[2]: Entering directory 'C:/Users/domin/Desktop/ueK_6/test.X'

15
"C:\Program Files\Microchip\xc8\v2.46\bin\xc8-cc.exe"  -mcpu=16F676 -Wl,-Map=dist/default/debug/test.X.debug.map  -D__DEBUG=1  -mdebugger=pickit3  -DXPRJ_default=default  -Wl,--defsym=__MPLAB_BUILD=1   -mdfp="C:/Program Files/Microchip/MPLABX/v6.20/packs/Microchip/PIC16Fxxx_DFP/1.6.156/xc8"  -fno-short-double -fno-short-float -fasmfile -maddrqual=ignore -xassembler-with-cpp -mwarn=-2 -Wa,-a -msummary=-psect,-class,+mem,-hex,-file  -ginhx32 -Wl,--data-init -mno-keep-startup -mno-osccal -mno-resetbits -mno-save-resetbits -mno-download -mno-stackcall -mdefault-config-bits -std=c99 -gdwarf-3 -mstack=compiled:auto:auto         -Wl,--memorysummary,dist/default/debug/memoryfile.xml -o dist/default/debug/test.X.debug.elf  build/default/debug/main.p1 build/default/debug/configuration_bits.p1     

16
::: advisory: (2100) using the C99 standard library with the selected device may result in larger code and data usage

17
main.c:177:: error: (800) undefined symbol "btemp"

18
(908) exit status = 1

19
make[2]: Leaving directory 'C:/Users/domin/Desktop/ueK_6/test.X'

20
21
BUILD FAILED (exit value 2, total time: 1s)




2) Code without error-search:
1
// -- INCLUDES ----------------------------------------------------------------

2
#include <xc.h>        // Compiler-Include (Port-Defines)

3
#include <stdbool.h>  // Include for data type 'bool' and keywords 'true' and 'false'

4
#include <stdint.h>   // Include for defines the standard integer types per ISO/IEC 9899:1999

5
6
// -- DEFINES -----------------------------------------------------------------

7
#define _XTAL_FREQ 10000000 // Crystal oscillator frequencies of 10Mhz

8
#define LOOP_DELAY 1000  // Loop-Delay in ms 

9
10
#define WARN_LED PORTCbits.RC2

11
12
#define SENSOR PORTAbits.RA2

13
#define SENSOR_TRIS TRISAbits.TRISA2

14
15
// -- FUNCTIONS-PROTOTYPE ----------------------------------------------------

16
uint8_t Read_DHT ( uint8_t *data );

17
18
// -- SETUP -------------------------------------------------------------------

19
20
void setup ( void )

21
{

22
    ANSEL = 0x00;

23
    TRISC = 0x00;

24
25
    SENSOR_TRIS = 1;

26
}

27
28
// -- LOOP ---------------------------------------------------------

29
30
void loop ( void )

31
{

32
33
34
    static uint8_t data[5] = { 0 };

35
36
    uint8_t result = Read_DHT( data );

37
    

38
    if ( result == 0 )

39
    {

40
        uint8_t int_RH = data[0];

41
        uint8_t dec_RH = data[1];

42
        uint8_t int_T = data[2];

43
        uint8_t dec_T = data[3];

44
45
46
        if ( int_RH > 75 )

47
        {

48
            WARN_LED = 1;

49
        }

50
        else

51
        {

52
            WARN_LED = 0;

53
        }

54
    }

55
}

56
57
// -- main -----------------------------------------------------------

58
59
void main ( void )

60
{

61
    setup( );

62
63
    // (Loop)

64
    while ( 1 )

65
    {

66
        loop( );

67
        __delay_ms( LOOP_DELAY );

68
    }

69
}

70
71
// -- FUNCTIONS --------------------------------------------------------------

72
73
uint8_t Read_DHT ( uint8_t *data )

74
{

75
76
77
    // SENSOR as OUTPUT

78
    SENSOR_TRIS = 0;

79
    SENSOR = 0;

80
    //wait 18ms

81
82
    __delay_ms( 18 );

83
84
    SENSOR = 1;

85
86
87
    __delay_us( 40 );

88
89
    // SENSOR as INPUT    

90
    SENSOR = 0;

91
92
    SENSOR_TRIS = 1;

93
94
    uint16_t timeout = 10000;

95
    while ( SENSOR == 1 )

96
    {

97
        if ( --timeout == 0 )

98
        {

99
            return 0x0F;

100
        }

101
    }

102
103
    timeout = 10000;

104
    while ( SENSOR == 0 )

105
    {

106
        if ( --timeout == 0 )

107
        {

108
            return 0xFF;

109
        }

110
    }

111
112
    timeout = 10000;

113
    while ( SENSOR == 1 )

114
    {

115
        if ( --timeout == 0 )

116
        {

117
            return 0xFF;

118
        }

119
    }

120
121
    for ( uint8_t i = 0; i < 5; i++ )

122
    {

123
        for ( int8_t j = 7; j >= 0; j-- )

124
        {

125
126
            timeout = 10000;

127
            while ( SENSOR == 0 )

128
            {

129
                if ( --timeout == 0 )

130
                {

131
                    return 0xFF;

132
                }

133
            }

134
            uint8_t signal_counter = 0;

135
            timeout = 10000;

136
            while ( SENSOR == 1 )

137
            {

138
                signal_counter++;

139
                __delay_us( 1 );

140
                if ( signal_counter > 100 )

141
                {

142
                    return 0xFE;

143
                }

144
            }

145
146
147
148
            if ( signal_counter > 30 )

149
            {

150
                data[i] |= (1 << j);

151
            }

152
        }

153
154
    }

155
    if ( ( uint8_t ) (data[0] + data[1] + data[2] + data[3]) != data[4] )

156
    {

157
        return 0xFF;

158
    }

159
160
    return 0;

161
162
163
}



3) Code with error-search
1
// -- INCLUDES ----------------------------------------------------------------

2
#include <xc.h>        // Compiler-Include (Port-Defines)

3
#include <stdbool.h>  // Include for data type 'bool' and keywords 'true' and 'false'

4
#include <stdint.h>   // Include for defines the standard integer types per ISO/IEC 9899:1999

5
6
// -- DEFINES -----------------------------------------------------------------

7
#define _XTAL_FREQ 10000000 // Crystal oscillator frequencies of 10Mhz

8
#define LOOP_DELAY 1000  // Loop-Delay in ms 

9
10
#define WARN_LED PORTCbits.RC2

11
12
#define SENSOR PORTAbits.RA2

13
#define SENSOR_TRIS TRISAbits.TRISA2

14
15
// -- FUNCTIONS-PROTOTYPE ----------------------------------------------------

16
uint8_t Read_DHT ( uint8_t *data );

17
18
// -- SETUP -------------------------------------------------------------------

19
20
void setup ( void )

21
{

22
    ANSEL = 0x00;

23
    TRISC = 0x00;

24
25
    SENSOR_TRIS = 1;

26
}

27
28
// --- loop ---------------------------------------------------------

29
30
void loop ( void )

31
{

32
33
34
    static uint8_t data[5] = { 0 };

35
36
    uint8_t result = Read_DHT( data );

37
    // Error 1

38
        if ( result == 0xFF )

39
        {

40
            while ( 1 )

41
            {

42
                    WARN_LED = 1;

43
                    __delay_ms( 2000 );

44
                    WARN_LED = 0;

45
                    __delay_ms( 2000 );

46
            }

47
        }

48
    

49
    // Error 2

50
        if ( result == 0x0F )

51
        {

52
            while ( 1 )

53
            {

54
                    WARN_LED = 1;

55
                    __delay_ms( 200 );

56
                    WARN_LED = 0;

57
                    __delay_ms( 200 );

58
            }

59
        }

60
61
    if ( result == 0 )

62
    {

63
        uint8_t int_RH = data[0];

64
        uint8_t dec_RH = data[1];

65
        uint8_t int_T = data[2];

66
        uint8_t dec_T = data[3];

67
68
69
        if ( int_RH > 75 )

70
        {

71
            WARN_LED = 1;

72
        }

73
        else

74
        {

75
            WARN_LED = 0;

76
        }

77
    }

78
}

79
80
// -- main -----------------------------------------------------------

81
82
void main ( void )

83
{

84
    setup( );

85
86
    // (Loop)

87
    while ( 1 )

88
    {

89
        loop( );

90
        __delay_ms( LOOP_DELAY );

91
    }

92
}

93
94
// -- FUNCTIONS --------------------------------------------------------------

95
96
uint8_t Read_DHT ( uint8_t *data )

97
{

98
99
100
    // SENSOR as OUTPUT

101
    SENSOR_TRIS = 0;

102
    SENSOR = 0;

103
    //wait 18ms

104
105
    __delay_ms( 18 );

106
107
    SENSOR = 1;

108
109
110
    __delay_us( 40 );

111
112
    // SENSOR as INPUT    

113
    SENSOR = 0;

114
115
    SENSOR_TRIS = 1;

116
117
    uint16_t timeout = 10000;

118
    while ( SENSOR == 1 )

119
    {

120
        if ( --timeout == 0 )

121
        {

122
            return 0x0F;

123
        }

124
    }

125
126
    timeout = 10000;

127
    while ( SENSOR == 0 )

128
    {

129
        if ( --timeout == 0 )

130
        {

131
            return 0xFF;

132
        }

133
    }

134
135
    timeout = 10000;

136
    while ( SENSOR == 1 )

137
    {

138
        if ( --timeout == 0 )

139
        {

140
            return 0xFF;

141
        }

142
    }

143
144
    for ( uint8_t i = 0; i < 5; i++ )

145
    {

146
        for ( int8_t j = 7; j >= 0; j-- )

147
        {

148
149
            timeout = 10000;

150
            while ( SENSOR == 0 )

151
            {

152
                if ( --timeout == 0 )

153
                {

154
                    return 0xFF;

155
                }

156
            }

157
            uint8_t signal_counter = 0;

158
            timeout = 10000;

159
            while ( SENSOR == 1 )

160
            {

161
                signal_counter++;

162
                __delay_us( 1 );

163
                if ( signal_counter > 100 )

164
                {

165
                    return 0xFE;

166
                }

167
            }

168
169
170
171
            if ( signal_counter > 30 )

172
            {

173
                data[i] |= (1 << j);

174
            }

175
        }

176
177
    }

178
    if ( ( uint8_t ) (data[0] + data[1] + data[2] + data[3]) != data[4] )

179
    {

180
        return 0xFF;

181
    }

182
183
    return 0;

184
185
186
}


  


  




  

    Report post Edit Move Thread sperren Anmeldepflicht aktivieren Anpinnen Delete topic Thread mit anderem zusammenführen Quote selected text Reply Reply with quote
  








    

    

       Watch this topic

      |
         Disable multi-page view

    

        


Please log in before posting. Registration is free and takes only a minute.



  Existing account

  


  
  

  
    

      

        
          
        
        
          
        
      

      

        
          
        
        
          
        
      

    


    
    
    





  Do you have a Google/GoogleMail account? No registration required!

  Log in with Google account
  





  No account? Register here.