Nathan Yonkee / Seeed_IR_Temp_Sensor

Class to read temperature measurements from Seeed Studio's IR temperature sensor

Dependents:   Seeed_Grove_4_Digit_Display_Clock

SeeedIRTempSensor.h@0:fa362542d13e, 2017-05-21 (annotated)

Committer:
tulanthoar
Date:
Sun May 21 19:44:02 2017 +0000
Revision:
0:fa362542d13e
initial commit

Who changed what in which revision?

UserRevisionLine numberNew contents of line
tulanthoar 0:fa362542d13e 1 /* #include <cmath> */
tulanthoar 0:fa362542d13e 2 #include "mbed.h"
tulanthoar 0:fa362542d13e 3 namespace IRTempSensor{
tulanthoar 0:fa362542d13e 4 #define SUR_TEMP_PIN PA_3 // Analog input pin connect to temperature sensor SUR pin
tulanthoar 0:fa362542d13e 5 #define OBJ_TEMP_PIN PC_0 // Analog input pin connect to temperature sensor OBJ pin
tulanthoar 0:fa362542d13e 6
tulanthoar 0:fa362542d13e 7 double measuresureTemp(PinName surPin) {
tulanthoar 0:fa362542d13e 8 AnalogIn surTPin(surPin);
tulanthoar 0:fa362542d13e 9 float volts, resistance, temperature;
tulanthoar 0:fa362542d13e 10 volts = 0;
tulanthoar 0:fa362542d13e 11 for (int i = 0; i < 100; i++) {
tulanthoar 0:fa362542d13e 12 volts += surTPin.read();
tulanthoar 0:fa362542d13e 13 wait_us(10);
tulanthoar 0:fa362542d13e 14 }
tulanthoar 0:fa362542d13e 15 volts *= 3.3/100;
tulanthoar 0:fa362542d13e 16 resistance = 2000000*volts/(2.5-volts);
tulanthoar 0:fa362542d13e 17 temperature = 1/(log(resistance/100000)/3964 +(1/298.15)) - 273.15;
tulanthoar 0:fa362542d13e 18 return temperature;
tulanthoar 0:fa362542d13e 19 }
tulanthoar 0:fa362542d13e 20
tulanthoar 0:fa362542d13e 21 float measureObjectTemp(PinName surPin, PinName objPin) {
tulanthoar 0:fa362542d13e 22 AnalogIn objTPin(objPin);
tulanthoar 0:fa362542d13e 23 float objV = 0;
tulanthoar 0:fa362542d13e 24 for (int i = 0; i < 100; i++) {
tulanthoar 0:fa362542d13e 25 objV += objTPin.read();
tulanthoar 0:fa362542d13e 26 wait_us(10);
tulanthoar 0:fa362542d13e 27 }
tulanthoar 0:fa362542d13e 28 objV *= 3.3/100;
tulanthoar 0:fa362542d13e 29 /* float pileSignal= objV - 2.5*17.4/(17.4+64); */
tulanthoar 0:fa362542d13e 30 float pileSignal = objV - 0.52;
tulanthoar 0:fa362542d13e 31 pileSignal *= 0.01;
tulanthoar 0:fa362542d13e 32 float ts = measuresureTemp(surPin) + 273.15;
tulanthoar 0:fa362542d13e 33 /* float calib = 1+(298.15 - ts)*0.0011; */
tulanthoar 0:fa362542d13e 34 float calib = 1;
tulanthoar 0:fa362542d13e 35 float k = 3.45*pow(10,-13)*calib;
tulanthoar 0:fa362542d13e 36 float kRecip = 2976078405624.9985;
tulanthoar 0:fa362542d13e 37 float kRecipAmp = kRecip * 0.01;
tulanthoar 0:fa362542d13e 38 /* float objT = (pileSignal*kRecip + ts*ts*ts*ts); */
tulanthoar 0:fa362542d13e 39 float objT = (objV*kRecipAmp -0.51*kRecipAmp + ts*ts*ts*ts);
tulanthoar 0:fa362542d13e 40 return pow(objT,0.25) - 273.15;
tulanthoar 0:fa362542d13e 41 /* return pileSignal*1000; */
tulanthoar 0:fa362542d13e 42 /* return objV*100; */
tulanthoar 0:fa362542d13e 43 }};