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DHT22 with proteus. #156

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DHT22 with proteus. #156

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15 changes: 15 additions & 0 deletions DHT.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -81,6 +81,7 @@ void DHT::begin(uint8_t usec) {
*/
float DHT::readTemperature(bool S, bool force) {
float f = NAN;
float a,b;

if (read(force)) {
switch (_type) {
Expand All @@ -105,6 +106,13 @@ float DHT::readTemperature(bool S, bool force) {
}
break;
case DHT22:
a = data[2]<<8;
b = data[3];
f = (a + b)/10;
if (S) {
f = convertCtoF(f);
}
break;
case DHT21:
f = ((word)(data[2] & 0x7F)) << 8 | data[3];
f *= 0.1;
Expand Down Expand Up @@ -144,13 +152,18 @@ float DHT::convertFtoC(float f) { return (f - 32) * 0.55555; }
*/
float DHT::readHumidity(bool force) {
float f = NAN;
float a,b;
if (read(force)) {
switch (_type) {
case DHT11:
case DHT12:
f = data[0] + data[1] * 0.1;
break;
case DHT22:
a = data[0]<<8;
b = data[1];
f = (a + b)/10;
break;
case DHT21:
f = ((word)data[0]) << 8 | data[1];
f *= 0.1;
Expand Down Expand Up @@ -254,6 +267,8 @@ bool DHT::read(bool force) {
digitalWrite(_pin, LOW);
switch (_type) {
case DHT22:
delay(20); // data sheet says at least 18ms, 20ms just to be safe
break;
case DHT21:
delayMicroseconds(1100); // data sheet says "at least 1ms"
break;
Expand Down