Revision 2:5628e75c533e, committed 2011-10-17

Comitter:

gbeardall

Date:

Mon Oct 17 10:41:44 2011 +0000

Parent:

1:bdb889fd3bef

Commit message:

Changed in this revision

diff -r bdb889fd3bef -r 5628e75c533e main.cpp
--- a/main.cpp	Thu Aug 25 12:46:50 2011 +0000
+++ b/main.cpp	Mon Oct 17 10:41:44 2011 +0000
@@ -3,18 +3,114 @@
  *
  */
 
+/*
++5 --------
+    |
+    |
+   +-+
+   | |      |\
+   | |->----|+\
+   | |      |  \--+----+------
+   +-+   +- |-/   |    |
+    |    |  |/    |   +-+
+    |    +--------+   | |
+0v ------             +_+
+                       |--------
+                      +-+
+                      | |
+                      +-+
+                       |
+
+
+
+*/ 
+
 #include "mbed.h"
 
 DigitalOut myled(LED1);
 
 AnalogIn hum(p20);
 AnalogIn ref(p19);
+AnalogIn tst(p18);
+
+//Timer timer;
+
 
 int main() {
     float av0 = 0.0;
-    float alpha = 0.5;
+    float alpha = 0.2;
+
+    printf("\rhumidity1: %u %u\n\r", sizeof(unsigned long long), sizeof(uint64_t) );
+
+    // decimation and downsamplig to reduce noise and increment resolution
 
-    printf("humidity1\n\r");
+    while(1) {
+        
+        //   32 - ? 8081
+        //   64 - 8 8082
+        //  128 - 6 807d
+        //  256 - 4 8071
+        //  512 - 2 805e
+        // 1024 - .3 803f
+        // 2048 - ? 8014
+        // 4096 - ? 7fe8
+        // 8192 - ? 7fca
+        // 16384 - ? 7fba
+        // 32768 - ? 7fb2
+        // 65536 - ? 7faf
+        // 131072 - ? 7fad
+        
+        // Sample values and their differences
+        // 7FB7 7FC7 7FD7 7FE7 7FF7 8008 8018 8028
+        //    10   10   10   10   11   10   10
+        
+        // Max conversion rate: 14KHz (~70us)
+        // ToDo        
+        // many samples to create new data set
+        // different sampling frequencies, see if effect same
+        //   measure raw sampling freq
+        // fourier analysis
+        // freq distribution
+        // overall and diff sized moving avg to see if effect is due to software.overflow or noise in data
+        // what does graph do at even larger sample sizes
+        // is there a temp drift?
+        
+        
+        //unsigned long long t = 0; // uint64_t
+        uint64_t t = 0;
+        uint64_t n = 1000; // 128/4096
+        //timer.start();
+        //float b1 = timer.read();
+        //int begin = timer.read_ms();
+        for(int i=0; i<n; ++i) {
+            //uint16_t v = tst.read_u16();
+            //uint64_t v = tst.read_u16();
+            uint64_t v = ref.read_u16();
+            //v >>= 4; // back to 12bits
+            
+            t += v;
+#if 0            
+            switch((v>>4)&0x01) {
+            case 0: wait_us(7); break;
+            case 1: wait_us(17); break;
+            default: printf("?");
+            } // switch
+#endif            
+        } // for 
+        //int end = timer.read_ms();
+        //float e1 = timer.read();
+        //printf("timer: %d %f %f\n\r", end-begin, e1-b1, (float)n*1000.0/(float)(end-begin) );
+
+        uint64_t x = t / n;
+        //t = t/(float)n;
+        
+        printf("%llu\n\r", x);
+        //printf("%.0f\n\r", t);
+        
+        //wait(4); // <<<<<<<<
+        
+        //wait_us(31);
+    }
 
     while(1) {
     
@@ -29,20 +125,24 @@
             r1 = ref.read();
             h += h1;
             r += r1;
-            v += 5.0*h1/r1; // convert to 5v reference
+            //v += 5.0*h1/r1; // convert to 5v reference
+            wait_us(100);
         }
         h /= n;
         r /= n;
-        v /= n;
+        //v /= n;
         
-        // EMA
+        v = 5.0*h/r; // convert to 5v reference
+
+        
+        // Exponential Moving Average
         float av = av0 + alpha*(v-av0);
         av0 = av;
         
         // scale to humidity%
         float m = (av-0.8)/3.0*100.0;
                 
-        printf("h=%1.4f r=%1.4f %1.4fv %1.4fv %3.1f%%\n\r", h, r, v, av, m );
+        printf("h=%1.4f r=%1.4f %1.4fv %1.4fv %3.2f%%\n\r", h, r, v, av, m );
     
         myled = 1;
         wait(0.2);