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ka's
1c0ffeb2ab
* Fixed incorrect value when temperature is negative. Corrected calculation by referring to the bit indicating whether the temperature is positive or negative (byte address 0x03, bit 8). * add new-line in end-of-file.
67 lines
1.2 KiB
C++
67 lines
1.2 KiB
C++
/*
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DHT12.cpp - Library for DHT12 sensor.
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v0.0.1 Beta
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Created by Bobadas, July 30,2016.
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Released into the public domain.
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*/
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#include "DHT12.h"
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DHT12::DHT12(uint8_t scale,uint8_t id)
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{
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if (id==0 || id>126) _id=0x5c;
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else _id=id;
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if (scale==0 || scale>3) _scale=CELSIUS;
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else _scale=scale;
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}
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uint8_t DHT12::read()
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{
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Wire.beginTransmission(_id);
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Wire.write(0);
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if (Wire.endTransmission()!=0) return 1;
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Wire.requestFrom(_id, (uint8_t)5);
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for (int i=0;i<5;i++) {
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datos[i]=Wire.read();
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};
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delay(50);
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if (Wire.available()!=0) return 2;
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if (datos[4]!=(datos[0]+datos[1]+datos[2]+datos[3])) return 3;
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return 0;
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}
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float DHT12::readTemperature(uint8_t scale)
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{
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float resultado=0;
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uint8_t error=read();
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if (error!=0) return (float)error/100;
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resultado=datos[2]+(float)(datos[3]&0x7f)/10;
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if(datos[3]&0x80)
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{
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resultado = -resultado;
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}
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if (scale==0) scale=_scale;
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switch(scale) {
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case CELSIUS:
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break;
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case FAHRENHEIT:
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resultado=resultado*1.8+32;
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break;
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case KELVIN:
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resultado=resultado+273.15;
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break;
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};
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return resultado;
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}
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float DHT12::readHumidity()
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{
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float resultado;
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uint8_t error=read();
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if (error!=0) return (float)error/100;
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resultado=(datos[0]+(float)datos[1]/10);
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return resultado;
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}
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