fix #102, support for KY015 (#103)

- fix #102, add support for KY015
- add three examples, dhtnew_dht11.ino, dhtnew_dht22.ino, dhtnew_simple.ino
- optimize decimal part DHT11 (type == 11)
- minor fix setType(23), could be bug.
- minor fix temperature conversion (-0.0)
- add offset functions with full name version (readability),
  - short ones will become obsolete in the future
- update readme.md

Author: RobTillaart

CHANGELOG.md

@@ -6,6 +6,16 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
 
+## [0.5.1] - 2024-11-24
+- fix #102, add support for KY015
+- add three examples, dhtnew_dht11.ino, dhtnew_dht22.ino, dhtnew_simple.ino
+- optimize decimal part DHT11 (type == 11)
+- minor fix setType(23), could be bug.
+- minor fix temperature conversion (-0.0)
+- add offset functions with full name version (readability),
+  - short ones will become obsolete in the future
+- update readme.md
+
 ## [0.5.0] - 2024-11-22
 - fix #100, different negative algorithm support
 - time to bump version

README.md

@@ -50,13 +50,27 @@ As the AM2321 and AM2322 are quite identical according to the datasheet, those a
 
 To use the library one should call **setType(22)** as the protocol is identical to the DHT22.
 If there are differences in operation type (23) will be elaborated.
-The value 23 is now mapped upon 22 code.
+The type 23 is now mapped upon type 22.
 
 Feedback (both positive and negative) about the AM232X sensors is welcome.
 
 **Note: check the datasheet how to connect!**
 
 
+### KY-015 (dht11)
+
+Since 0.5.1 there is support for the KY-015. Although it is a DHT11, the KY-015 behaves slightly 
+different (faster wakeup) and was recognized as a DHT22 resulting in faulty conversions.
+The library sensor recognition code has been adapted so it should be recognized now.
+In the case the recognition fails, one can use **setType(11)** to force the type.
+
+The KY-015 is confirmed to work, see https://github.com/RobTillaart/DHTNew/issues/102
+
+Feedback about the KY-015 sensors is welcome.
+
+**Note: check the datasheet how to connect!**
+
+
 ### 0.5.0 Negative temperature
 
 Apparently there are DHT22's which use another representation for negative temperatures.
@@ -69,9 +83,13 @@ See also https://arduino.stackexchange.com/questions/86448/dht22-sensor-reading-
 
 ### Related
 
-- https://github.com/RobTillaart/DHTNew
-- https://github.com/RobTillaart/DHTStable
+- https://github.com/RobTillaart/DHTNew DHT11/22 etc
+- https://github.com/RobTillaart/DHTStable DHT11/22 etc
 - https://github.com/RobTillaart/DHT_Simulator
+- https://github.com/RobTillaart/DS18B20_INT OneWire temperature sensor
+- https://github.com/RobTillaart/DS18B20_RT OneWire temperature sensor
+- https://github.com/RobTillaart/SHT31 Sensirion humidity / temperature sensor
+- https://github.com/RobTillaart/SHT85 Sensirion humidity / temperature sensor
 - https://www.kandrsmith.org/RJS/Misc/Hygrometers/calib_many.html (interesting)
 - https://github.com/RobTillaart/Temperature (conversions, dewPoint, heat index etc.)
 
@@ -85,11 +103,13 @@ See also https://arduino.stackexchange.com/questions/86448/dht22-sensor-reading-
 |  pin 3  |      |  Not Connected  |
 |  pin 4  |      |  GND            |
 
-**Note: check the datasheet how to connect!**
+**Note: check the datasheet of the sensor how to connect!** as some have only 3 pins.
 
 
 ## Specification DHT22
 
+As most used model, for other sensors I refer to datasheet.
+
 |  Model                      |  DHT22                   |  Notes  |
 |:----------------------------|:-------------------------|:--------|
 |  Power supply               |  3.3 - 6.0 V DC          |
@@ -115,21 +135,22 @@ See also https://arduino.stackexchange.com/questions/86448/dht22-sensor-reading-
 ### Constructor
 
 - **DHTNEW(uint8_t pin)** defines the dataPin of the sensor.
-- **void reset()** might help to reset a sensor behaving badly. It does reset the library settings to default, 
+- **void reset()** might help to reset a sensor behaving badly. 
+It resets the library internal settings to default, 
 however it does not reset the sensor in a hardware way. 
 - **uint8_t getType()**  0 = unknown, 11 or 22. 
 In case of 0, **getType()** will try to determine type.
 Since 0.4.14 type 70 is added for **experimental** Sonoff Si7021 support.
 - **void setType(uint8_t type = 0)** allows to force the type of the sensor. 
 
-|  Type   |  Sensors        |  Notes  |
-|:-------:|:---------------:|:--------|
-|   0     |  not defined    |
-|   11    |  DHT11          |
-|   22    |  DHT22 a.o      |  most others
-|   23    |  DHT22 a.o      |  mapped to 22 for now
-|   70    |  Sonoff Si7021  |  experimental
-|  other  |  sets to 0      |  0.4.20
+|  Type   |  Sensors                  |  Notes  |
+|:-------:|:-------------------------:|:--------|
+|   0     |  not defined              |
+|   11    |  DHT11 DHT12, KY015       |  KY015 needs setType(11)
+|   22    |  DHT22, DHT33, DHT44 a.o  |  most others
+|   23    |  DHT23                    |  mapped to 22 for now
+|   70    |  Sonoff Si7021            |  experimental
+|  other  |  sets to 0                |  0.4.20
 
 
 ### Base interface
@@ -149,10 +170,19 @@ Note this error value can be suppressed by **setSuppressError(bool)**.
 
 Adding offsets works well in normal range however they might introduce 
 under- or overflow at the ends of the sensor range.
-Humidity is in % RH.
-Humidity is constrained to 0.0 - 100.0 % in the code.
-Temperature is in degrees Celsius.
-For temperature such constrain would be type dependant, so it is not done.
+
+Humidity offset is in % RH and is constrained to 0.0 - 100.0 % in the code.
+
+Temperature offset is in degrees Celsius.
+For temperature a constrain would be type dependant, so it is not done.
+Furthermore by setting the offset to -273.15 one get the **Kelvin** scale.
+
+- **void setHumidityOffset(float offset)** typical < ±5% RH.
+- **void setTemperatureOffset(float offset)** typical < ±2°C.
+- **float getHumidityOffset()** idem.
+- **float getTemperatureOffset()** idem.
+
+The "short-named" offset functions will become obsolete in the future (0.6.0).
 
 - **void setHumOffset(float offset)** typical < ±5% RH.
 - **void setTempOffset(float offset)** typical < ±2°C.
@@ -311,7 +341,7 @@ updated readme.md - added badges and remarks after testing with MKR1010 Wifi.
 updated TIMEOUT_C from 70 -> 90 us to minimize its occurrence - See https://github.com/RobTillaart/DHTNew/issues/67.
 added ```while(!Serial);``` in examples to they work for MKR1010 Wifi.
 27. (0.4.11)
-update library.json, license, minor edits (cleanup), unit tests
+update library.json, license, minor edits (clean up), unit tests
 28. (0.4.12)
 Fix #72, delayMicroseconds() for wakeUp
 29. (0.4.13)
@@ -332,6 +362,10 @@ Update readme.md
 Update GitHub actions and readme.md
 36. (0.4.21)
 Add dhtnew_pulse_diag_ext.ino
+37. (0.5.0)
+Fix negative values
+38. (0.5.1)
+Support KY015 and more.
 
 
 ## Future
@@ -360,11 +394,17 @@ if (type == 11) temp = constrain(temp,   0, 100);
 if (type == 22) temp = constrain(temp, -40,  80);
 etc.
 ```
-
+- type parameter in constructor, default 0
+- reimplement the recognition algorithm (separate class?)
+  - read as 22 => check the hum / temp data range to determine type
+  - read as 11 => check idem
+  - read as 70 => check idem
+  - split wakeup time from bit interpretation used.
 
 #### Wont
 
 - move all code from .h to .cpp
+- derived classes for fixed type?
 
 
 ## Support

dhtnew.cpp

@@ -1,7 +1,7 @@
 //
 //    FILE: dhtnew.cpp
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.5.0
+// VERSION: 0.5.1
 // PURPOSE: DHT Temperature & Humidity Sensor library for Arduino
 //     URL: https://github.com/RobTillaart/DHTNEW
 //
@@ -13,6 +13,7 @@
 
 
 //  these defines are not for user to adjust (microseconds)
+//  it adds 10% above the data sheet to allow a margin.
 #define DHTLIB_DHT11_WAKEUP           (18 * 1100UL)
 #define DHTLIB_DHT_WAKEUP             (1 * 1100UL)
 //  experimental 0.4.14
@@ -45,19 +46,20 @@ void DHTNEW::reset()
   pinMode(_dataPin, OUTPUT);
   digitalWrite(_dataPin, HIGH);
 
-  _wakeupDelay   = 0;
-  _type          = 0;
-  _humOffset     = 0.0;
-  _tempOffset    = 0.0;
-  _humidity      = 0.0;
-  _temperature   = 0.0;
-  _lastRead      = 0;
-  _disableIRQ    = true;
-  _waitForRead   = false;
-  _suppressError = false;
-  _readDelay     = 0;
+  _wakeupDelay    = 0;
+  _type           = 0;
+  _humidityOffset = 0.0;
+  _temperatureOffset = 0.0;
+  _humidity       = 0.0;
+  _temperature    = 0.0;
+  _lastRead       = 0;
+  _disableIRQ     = true;
+  _waitForRead    = false;
+  _suppressError  = false;
+  _readDelay      = 0;
 #if defined(__AVR__)
-  _disableIRQ    = false;
+  //  overrule
+  _disableIRQ     = false;
 #endif
 // #if defined(ARDUINO_SAMD_MKRWIFI1010)  //  fix for issue #67
   // _disableIRQ    = false;
@@ -80,7 +82,7 @@ void DHTNEW::setType(uint8_t type)
 
   if ((type == 22) || (type == 23))
   {
-    _type = type;
+    _type = 22;  //  cannot differentiate type;
     _wakeupDelay = DHTLIB_DHT_WAKEUP;
   }
   else if (type == 11)
@@ -125,27 +127,51 @@ int DHTNEW::read()
   }
 
   //  AUTODETECT
-  //  make sure sensor had time to wake up.
+  //  make sure sensor had time to wake up after start of sketch.
   while (millis() < 1000);
 
+  //  NOTE: we could add conversion H and T here and
+  //        check if these are in the allowed range.
+  //        humidity 0..100%,   temperature 0..80C or -40..80C
+  //        drawback: would increase footprint.
+
   //  NOTE: cannot differentiate between type 23 and 22
   _type = 22;
   _wakeupDelay = DHTLIB_DHT_WAKEUP;
   int rv = _read();
-  if (rv == DHTLIB_OK) return rv;
+  if (rv == DHTLIB_OK)
+  {
+    //  see issue #102
+    //  test high humidity bits to check for KY015/ DHT11 encoding
+    //  in DHT22 encoding humidity cannot be over 100.0 % == 0x03E8
+    //  so the high bits cannot be over 0x03
+    //  test can incorrectly fail if there is an extreme low humidity
+    //  note desert air still has about ~20% RH
+    if (_bits[0] <= 0x03)
+    {
+      return rv;
+    }
+    //  fall through to test KY015 as DHT11
+  }
 
   _type = 11;
   _wakeupDelay = DHTLIB_DHT11_WAKEUP;
   rv = _read();
-  if (rv == DHTLIB_OK) return rv;
+  if (rv == DHTLIB_OK)
+  {
+    return rv;
+  }
 
   //  experimental 0.4.14
   _type = 70;
   _wakeupDelay = DHTLIB_SI7021_WAKEUP;
   rv = _read();
-  if (rv == DHTLIB_OK) return rv;
+  if (rv == DHTLIB_OK)
+  {
+    return rv;
+  }
 
-  _type = 0; // retry next time
+  _type = 0;  //  retry next time
   return rv;
 }
 
@@ -185,10 +211,12 @@ int DHTNEW::_read()
     return rv;        //  propagate error value
   }
 
-  if (_type == 11)    //  DHT11, DH12, compatible
+  if (_type == 11)    //  DHT11, DH12, KY015 compatible
   {
-    _humidity    = _bits[0] + _bits[1] * 0.1;
-    _temperature = _bits[2] + _bits[3] * 0.1;
+    _humidity    = _bits[0];
+    if (_bits[1]) _humidity += _bits[1] * 0.1;
+    _temperature = _bits[2];
+    if (_bits[3]) _temperature += _bits[3] * 0.1;
   }
   else               //  DHT22, DHT33, DHT44, compatible + Si7021
   {
@@ -198,11 +226,15 @@ int DHTNEW::_read()
     if ((_bits[2] & 0x80) != 0x80 )
     {
       int16_t t = ((_bits[2] & 0x7F) * 256 + _bits[3]);
+      //  prevent -0.0;
       if (t == 0)
       {
-        _temperature = 0.0;     //  prevent -0.0;
+        _temperature = 0.0;
+      }
+      else
+      {
+        _temperature = t * 0.1;
       }
-      _temperature = t * 0.1;
     }
     else  //  negative temperature
     {
@@ -257,15 +289,16 @@ int DHTNEW::_read()
   }
 #endif
 
-  if (_humOffset != 0.0)
+  if (_humidityOffset != 0.0)
   {
-    _humidity += _humOffset;
+    _humidity += _humidityOffset;
+    //  constrain range
     if (_humidity > 100)    _humidity = 100;
     else if (_humidity < 0) _humidity = 0;
   }
-  if (_tempOffset != 0.0)
+  if (_temperatureOffset != 0.0)
   {
-    _temperature += _tempOffset;
+    _temperature += _temperatureOffset;
   }
 
   //  TEST CHECKSUM