main.cpp

00001 #include "mbed.h"
00002 // This piece of software decode Weahter station temperature and humidity
00003 // freeware, by Lotfi BAGHLI, March, 2013
00004 // I hacked the TX WT440H, got 2 wires out (GND and DATA)
00005 // I still want to get the data from a RX one (WS738) or a simple 433 MHz RX but signal pbs not yet solved
00006 //
00007 // thanks to Jaakko Ala-Paavola, http://ala-paavola.fi/jaakko/doku.php?id=wt450h
00008 // for the protocol and decode routine
00009 //
00010 // Connect 2 wires to the MBED : GND and Data Signal to p18
00011 // Temperature and Humidity are displayed on the Serial via USB of the MBED
00012 
00013 DigitalOut myled(LED1);
00014 DigitalOut led2(LED2);
00015 DigitalIn Rx433(p18);
00016 InterruptIn Rx433NotifyChange(p18);
00017 Serial pc(USBTX, USBRX);
00018 Timer T3;
00019 
00020 #define TIMEOUT 1000
00021 #define BIT0_LENGTH 2000
00022 #define BIT1_LENGTH 1000
00023 #define VARIATION 500
00024 #define DATA_LENGTH 5
00025 #define SENSOR_COUNT 4
00026 #define NETWORK_COUNT 2
00027 #define MSGLENGTH 36
00028 
00029 //#define DEBUG
00030 struct sensor {
00031     unsigned char humidity;
00032     signed char   temp_int;
00033     unsigned char temp_dec;
00034     signed char   min_int;
00035     unsigned char min_dec;
00036     signed char   max_int;
00037     unsigned char max_dec;
00038     time_t timestamp;
00039 };
00040 unsigned long T3saved_us;
00041 unsigned char bitcount = 0;
00042 unsigned char bytecount = 0;
00043 unsigned char second_half = 0;
00044 unsigned char data[DATA_LENGTH];
00045 struct sensor measurement[NETWORK_COUNT][SENSOR_COUNT];
00046 unsigned char minmaxday = 0;
00047 // make var global
00048 time_t t;
00049 unsigned char net, id;
00050 int t_int;
00051 unsigned char rh, t_dec;
00052 
00053 unsigned int i,j, oldj;
00054 
00055 void NCInterrupt()
00056 {
00057     unsigned char i;
00058     unsigned char bit;
00059     unsigned long current = T3.read_us();
00060     unsigned long diff = current-T3saved_us;
00061     myled = ! myled;
00062     j++;
00063     T3saved_us=current;
00064 
00065 
00066     if ( diff < BIT0_LENGTH + VARIATION && diff > BIT0_LENGTH - VARIATION ) {
00067         bit = 0;
00068         second_half = 0;
00069     } else if ( diff < BIT1_LENGTH + VARIATION && diff > BIT1_LENGTH - VARIATION ) {
00070         if (second_half) {
00071             bit = 1;
00072             second_half = 0;
00073         } else {
00074             second_half = 1;
00075             return;
00076         }
00077     } else {
00078         goto reset;
00079     }
00080 
00081     data[bitcount/8] = data[bitcount/8]<<1;
00082     data[bitcount/8] |= bit;
00083     bitcount++;
00084 
00085     if ( bitcount == 4 ) {
00086         if ( data[0] != 0x0c )
00087             goto reset;
00088         bitcount = 8;
00089 #ifdef DEBUG
00090         pc.print('#');
00091 #endif
00092     }
00093 
00094     if ( bitcount >= MSGLENGTH ) {
00095 
00096 #ifdef DEBUG
00097         for (i=0; i<DATA_LENGTH; i++) {
00098             pc.print(data[i], HEX);
00099             pc.print(' ');
00100         }
00101 #endif
00102 //       pc.print("Data: NET:");
00103         net = 0x07 & (data[1]>>4)-1;
00104 //       pc.print(net,DEC);
00105 //       pc.print(" ID:");
00106         id = 0x03 & (data[1]>>2);
00107 //       pc.print(id, DEC);
00108 //       pc.print(" RH:");
00109         rh = data[2];
00110 //       pc.print(rh, DEC);
00111 //       pc.print(" T:");
00112         t_int = data[3]-50;
00113 //       pc.print(t_int, DEC);
00114         t_dec = data[4]>>1;
00115 //       pc.print('.');
00116 //       pc.print(t_dec,DEC);
00117 
00118         t = time(NULL);
00119 
00120         /* Do not store all sensors */
00121 
00122         if ( net <= NETWORK_COUNT ) {
00123             measurement[net][id].temp_int = t_int;
00124             measurement[net][id].temp_dec = t_dec;
00125             measurement[net][id].humidity = rh;
00126             /*
00127                         if ( !measurement[net][id].timestamp ||
00128                                 day(t) != minmaxday ) {
00129                             minmaxday = day(t);
00130                             measurement[net][id].max_int = t_int;
00131                             measurement[net][id].max_dec = t_dec;
00132                             measurement[net][id].min_int = t_int;
00133                             measurement[net][id].min_dec = t_dec;
00134                         }
00135 
00136                         if ( t_int > measurement[net][id].max_int ||
00137                                 ( t_int == measurement[net][id].max_int && t_dec > measurement[net][id].max_dec ) ) {
00138                             measurement[net][id].max_int = t_int;
00139                             measurement[net][id].max_dec = t_dec;
00140                         }
00141 
00142                         if ( t_int < measurement[net][id].min_int ||
00143                                 ( t_int == measurement[net][id].min_int && t_dec < measurement[net][id].min_dec ) ) {
00144                             measurement[net][id].min_int = t_int;
00145                             measurement[net][id].min_dec = t_dec;
00146                         }
00147             */
00148 
00149             measurement[net][id].timestamp = t;
00150         }
00151 
00152         goto reset;
00153     }
00154     return;
00155 
00156 reset:
00157     for (i=0; i<DATA_LENGTH; i++)
00158         data[i] = 0;
00159 
00160     bytecount = 0;
00161     bitcount = 0;
00162     second_half = 0;
00163     return;
00164 }
00165 
00166 int main()
00167 {
00168     j=0;
00169     T3.start();
00170     pc.baud(115200);
00171     Rx433NotifyChange.mode(PullNone);
00172     Rx433NotifyChange.rise(&NCInterrupt);
00173     Rx433NotifyChange.fall(&NCInterrupt);
00174     while(1) {
00175         led2 = !led2;
00176         wait(1);
00177         if (oldj != j)
00178             {
00179         pc.printf("j:%d, Data: NET:%d ID:%d RH:%d T:%d.%d  TIME:%s\r", j, net, id, rh, t_int, t_dec, ctime(&t));
00180         oldj=j;
00181         }
00182 
00183     }
00184 }