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Merge pull request #125 from sijskes/master

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fixed incorrect values on DHT11 below 0 degrees celcius
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Paint Your Dragon 2019-02-14 09:03:16 -08:00 committed by GitHub
commit 1e752b12ee
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1 changed files with 12 additions and 3 deletions
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DHT.cpp
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@ -39,6 +39,15 @@ float DHT::readTemperature(bool S, bool force) {
if (read(force)) { if (read(force)) {
switch (_type) { switch (_type) {
case DHT11: case DHT11:
f = data[2];
if (data[3] & 0x80) {
f = -1 - f ;
}
f += (data[3] & 0x0f) * 0.1;
if(S) {
f = convertCtoF(f);
}
break;
case DHT12: case DHT12:
f = data[2]; f = data[2];
f += (data[3] & 0x0f) * 0.1; f += (data[3] & 0x0f) * 0.1;
@ -155,11 +164,11 @@ bool DHT::read(bool force) {
pinMode(_pin, OUTPUT); pinMode(_pin, OUTPUT);
digitalWrite(_pin, LOW); digitalWrite(_pin, LOW);
switch(_type) { switch(_type) {
case DHT22: case DHT22:
case DHT21: case DHT21:
delayMicroseconds(1100); // data sheet says "at least 1ms" delayMicroseconds(1100); // data sheet says "at least 1ms"
break; break;
case DHT11: case DHT11:
default: default:
delay(20); //data sheet says at least 18ms, 20ms just to be safe delay(20); //data sheet says at least 18ms, 20ms just to be safe
break; break;