Cumulocity Official / Mbed 2 deprecated MbedSmartRestMain Featured

Official reference client implementation for Cumulocity SmartREST on u-blox C027.

Dependencies:   C027_Support C12832 LM75B MMA7660 MbedSmartRest mbed-rtos mbed

Fork of MbedSmartRestMain by Vincent Wochnik

measurement/Potentiometer.cpp@115:c54e9731b9de, 2015-05-15 (annotated)

Committer:
xinlei
Date:
Fri May 15 15:09:19 2015 +0000
Revision:
115:c54e9731b9de
Parent:
114:80610be056e2
Child:
117:5de54f09f754
speed up pots sampling when no noticeable change

Who changed what in which revision?

UserRevisionLine numberNew contents of line
xinlei 101:dbcd3bc51758 1 #include <stdio.h>
xinlei 113:3872569be2af 2 #include "rtos.h"
xinlei 101:dbcd3bc51758 3 #include "Potentiometer.h"
xinlei 101:dbcd3bc51758 4 #include "SmartRestConf.h"
xinlei 101:dbcd3bc51758 5 #include "logging.h"
xinlei 101:dbcd3bc51758 6
xinlei 101:dbcd3bc51758 7 // Cutoff for avoiding sending similar sensor data.
xinlei 101:dbcd3bc51758 8 #define THRESHOLD_PERCENT_ANA 0.02
xinlei 101:dbcd3bc51758 9 // Timeout for forcing a sending even if readings are similar [seconds]
xinlei 101:dbcd3bc51758 10 #define TIME_LIMIT_ANA 900
xinlei 101:dbcd3bc51758 11
xinlei 101:dbcd3bc51758 12 AnalogIn analog1(A0);
xinlei 101:dbcd3bc51758 13 AnalogIn analog2(A1);
xinlei 101:dbcd3bc51758 14
xinlei 115:c54e9731b9de 15 static inline bool valueChanged(float *V0, float *V1)
xinlei 115:c54e9731b9de 16 {
xinlei 115:c54e9731b9de 17 if (abs(V0[0]-V1[0]) <= abs(V0[0])*THRESHOLD_PERCENT_ANA &&
xinlei 115:c54e9731b9de 18 abs(V0[1]-V1[1]) <= abs(V0[1])*THRESHOLD_PERCENT_ANA)
xinlei 115:c54e9731b9de 19 return false;
xinlei 115:c54e9731b9de 20 else
xinlei 115:c54e9731b9de 21 return true;
xinlei 115:c54e9731b9de 22 }
xinlei 115:c54e9731b9de 23
xinlei 101:dbcd3bc51758 24 size_t Potentiometer::read(char *buf, size_t maxLen, char *status, size_t num)
xinlei 101:dbcd3bc51758 25 {
xinlei 101:dbcd3bc51758 26 static const char *fmt = "107,%ld,%f,%f\r\n";
xinlei 115:c54e9731b9de 27 float data[2] = {(float)analog1*100, (float)analog2*100};
xinlei 115:c54e9731b9de 28 if (!valueChanged(oldValues, data)) {
xinlei 101:dbcd3bc51758 29 time_t t_interval = time(NULL) - t_start;
xinlei 101:dbcd3bc51758 30 if (t_interval < TIME_LIMIT_ANA) {
xinlei 101:dbcd3bc51758 31 return 0;
xinlei 101:dbcd3bc51758 32 } else {
xinlei 101:dbcd3bc51758 33 aDebug("Poti: Timeout at %d s.\n", t_interval);
xinlei 101:dbcd3bc51758 34 }
xinlei 115:c54e9731b9de 35 } else {
xinlei 115:c54e9731b9de 36 float min[2] = {100, 100};
xinlei 115:c54e9731b9de 37 float max[2] = {0, 0};
xinlei 115:c54e9731b9de 38 data[0] = 0;
xinlei 115:c54e9731b9de 39 data[1] = 0;
xinlei 115:c54e9731b9de 40 // multiple sampling for data smoothing
xinlei 115:c54e9731b9de 41 const unsigned short N = 10;
xinlei 115:c54e9731b9de 42 for (unsigned short i = 0; i < N; ++i) {
xinlei 115:c54e9731b9de 43 float d0 = (float)analog1*100;
xinlei 115:c54e9731b9de 44 float d1 = (float)analog2*100;
xinlei 115:c54e9731b9de 45 data[0] += d0;
xinlei 115:c54e9731b9de 46 data[1] += d1;
xinlei 115:c54e9731b9de 47 min[0] = min[0] <= d0 ? min[0] : d0;
xinlei 115:c54e9731b9de 48 min[1] = min[1] <= d1 ? min[1] : d1;
xinlei 115:c54e9731b9de 49 max[0] = max[0] >= d0 ? max[0] : d0;
xinlei 115:c54e9731b9de 50 max[1] = max[1] >= d1 ? max[1] : d1;
xinlei 115:c54e9731b9de 51 Thread::wait(10);
xinlei 115:c54e9731b9de 52 }
xinlei 115:c54e9731b9de 53 data[0] = (data[0]-min[0]-max[0]) / (N-2);
xinlei 115:c54e9731b9de 54 data[1] = (data[1]-min[1]-max[1]) / (N-2);
xinlei 115:c54e9731b9de 55 if (!valueChanged(oldValues, data))
xinlei 115:c54e9731b9de 56 return 0;
xinlei 101:dbcd3bc51758 57 }
xinlei 101:dbcd3bc51758 58
xinlei 101:dbcd3bc51758 59 size_t l = snprintf(buf, maxLen, fmt, deviceID, data[0], data[1]);
xinlei 101:dbcd3bc51758 60 if (status) {
xinlei 101:dbcd3bc51758 61 snprintf(status, num, "Send Poti %.1f,%.1f", data[0], data[1]);
xinlei 101:dbcd3bc51758 62 }
xinlei 101:dbcd3bc51758 63 oldValues[0] = data[0];
xinlei 101:dbcd3bc51758 64 oldValues[1] = data[1];
xinlei 101:dbcd3bc51758 65 t_start = time(NULL);
xinlei 101:dbcd3bc51758 66 return l;
xinlei 101:dbcd3bc51758 67 }