Lieven Hollevoet / QW_Sensors

Clone of the Quicksand QW Sensors library

Fork of QW_Sensors by Quicksand micro-electronics

LinearTempSensor.cpp@3:7fb6f774bf68, 2016-03-08 (annotated)

Committer:
LievenHollevoet
Date:
Tue Mar 08 09:45:50 2016 +0000
Revision:
3:7fb6f774bf68
Parent:
0:4b56d28cc7e9 
Moved the main to one level higher to be able to import the library in other programs.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
quicksand 0:4b56d28cc7e9 1 /* mbed Linear Temperature Sensor library
quicksand 0:4b56d28cc7e9 2 * Supports Microchip MCP9700/9701, National Semiconductor LM35
quicksand 0:4b56d28cc7e9 3 *
quicksand 0:4b56d28cc7e9 4 * Written by Todotani, Nov 22 2010
quicksand 0:4b56d28cc7e9 5 */
quicksand 0:4b56d28cc7e9 6
quicksand 0:4b56d28cc7e9 7 #include "LinearTempSensor.h"
quicksand 0:4b56d28cc7e9 8
quicksand 0:4b56d28cc7e9 9 LinearTempSensor::LinearTempSensor(PinName ain, int N, SensorType type):
quicksand 0:4b56d28cc7e9 10 // Initialize private variables using Initialization Lists
quicksand 0:4b56d28cc7e9 11 // _ain(ain) is equivalent to _ain = new AnalogIn(ain)
quicksand 0:4b56d28cc7e9 12 // _sample(N) is equivalent to _sample = N
quicksand 0:4b56d28cc7e9 13 _ain(ain), _samples(N), _type(type) {
quicksand 0:4b56d28cc7e9 14 sampleBuffer = (float *)malloc(sizeof(float) * _samples);
quicksand 0:4b56d28cc7e9 15 sampleCount = 0;
quicksand 0:4b56d28cc7e9 16 index = 0;
quicksand 0:4b56d28cc7e9 17 Vref = 3300;
quicksand 0:4b56d28cc7e9 18 bufferNotFilled = true;
quicksand 0:4b56d28cc7e9 19
quicksand 0:4b56d28cc7e9 20 // Set constants to calculate temperature from sensor value
quicksand 0:4b56d28cc7e9 21 switch (_type) {
quicksand 0:4b56d28cc7e9 22 case LM35:
quicksand 0:4b56d28cc7e9 23 V0 = 0.0f;
quicksand 0:4b56d28cc7e9 24 Tc = 10.0f;
quicksand 0:4b56d28cc7e9 25 break;
quicksand 0:4b56d28cc7e9 26 case MCP9701:
quicksand 0:4b56d28cc7e9 27 V0 = 400.0f;
quicksand 0:4b56d28cc7e9 28 Tc = 19.5f;
quicksand 0:4b56d28cc7e9 29 break;
quicksand 0:4b56d28cc7e9 30 case MCP9700:
quicksand 0:4b56d28cc7e9 31 default:
quicksand 0:4b56d28cc7e9 32 V0 = 500.0f;
quicksand 0:4b56d28cc7e9 33 Tc = 10.0f;
quicksand 0:4b56d28cc7e9 34 }
quicksand 0:4b56d28cc7e9 35
quicksand 0:4b56d28cc7e9 36 for (int i = 0; i < _samples; i++)
quicksand 0:4b56d28cc7e9 37 sampleBuffer[i] = 0.0f;
quicksand 0:4b56d28cc7e9 38 }
quicksand 0:4b56d28cc7e9 39
quicksand 0:4b56d28cc7e9 40
quicksand 0:4b56d28cc7e9 41 LinearTempSensor::~LinearTempSensor() {
quicksand 0:4b56d28cc7e9 42 free(sampleBuffer);
quicksand 0:4b56d28cc7e9 43 }
quicksand 0:4b56d28cc7e9 44
quicksand 0:4b56d28cc7e9 45
quicksand 0:4b56d28cc7e9 46 float LinearTempSensor::Sense() {
quicksand 0:4b56d28cc7e9 47 float val;
quicksand 0:4b56d28cc7e9 48
quicksand 0:4b56d28cc7e9 49 val = _ain * Vref;
quicksand 0:4b56d28cc7e9 50 sampleBuffer[index] = val;
quicksand 0:4b56d28cc7e9 51 //printf("Index:%d ", index); // Debug print
quicksand 0:4b56d28cc7e9 52 if ( ++index >= _samples )
quicksand 0:4b56d28cc7e9 53 index = 0;
quicksand 0:4b56d28cc7e9 54
quicksand 0:4b56d28cc7e9 55 if ( bufferNotFilled && (sampleCount == _samples) ) {
quicksand 0:4b56d28cc7e9 56 bufferNotFilled = false;
quicksand 0:4b56d28cc7e9 57 }
quicksand 0:4b56d28cc7e9 58 //printf("flag:%d ", bufferNotFilled); // Debug print
quicksand 0:4b56d28cc7e9 59 sampleCount++;
quicksand 0:4b56d28cc7e9 60
quicksand 0:4b56d28cc7e9 61 return val;
quicksand 0:4b56d28cc7e9 62 }
quicksand 0:4b56d28cc7e9 63
quicksand 0:4b56d28cc7e9 64
quicksand 0:4b56d28cc7e9 65 float LinearTempSensor::GetAverageTemp() {
quicksand 0:4b56d28cc7e9 66 float sum = 0;
quicksand 0:4b56d28cc7e9 67 int i, numberOfsumples;
quicksand 0:4b56d28cc7e9 68
quicksand 0:4b56d28cc7e9 69 if (sampleCount == 0)
quicksand 0:4b56d28cc7e9 70 return 0;
quicksand 0:4b56d28cc7e9 71
quicksand 0:4b56d28cc7e9 72 if (bufferNotFilled) {
quicksand 0:4b56d28cc7e9 73 // In case number of samples less than buffer lenght
quicksand 0:4b56d28cc7e9 74 for (i = 0; i < sampleCount; i++) {
quicksand 0:4b56d28cc7e9 75 sum += sampleBuffer[i];
quicksand 0:4b56d28cc7e9 76 }
quicksand 0:4b56d28cc7e9 77 numberOfsumples = sampleCount;
quicksand 0:4b56d28cc7e9 78 } else {
quicksand 0:4b56d28cc7e9 79 // In case buffer is filled
quicksand 0:4b56d28cc7e9 80 for (i = 0; i < _samples; i++) {
quicksand 0:4b56d28cc7e9 81 sum += sampleBuffer[i];
quicksand 0:4b56d28cc7e9 82 }
quicksand 0:4b56d28cc7e9 83 numberOfsumples = _samples;
quicksand 0:4b56d28cc7e9 84 }
quicksand 0:4b56d28cc7e9 85
quicksand 0:4b56d28cc7e9 86 return ((sum / numberOfsumples) - V0) / Tc; // Temp = (Vout - V0) / Tc
quicksand 0:4b56d28cc7e9 87 }
quicksand 0:4b56d28cc7e9 88
quicksand 0:4b56d28cc7e9 89
quicksand 0:4b56d28cc7e9 90 float LinearTempSensor::GetLatestTemp() {
quicksand 0:4b56d28cc7e9 91 return (sampleBuffer[(sampleCount-1)%_samples] - V0) / Tc;
quicksand 0:4b56d28cc7e9 92 }