Version 0.1.13

latest stable for AVR & ARM

libraries/DHTstable/dht.cpp

@@ -0,0 +1,169 @@
+//
+//    FILE: dht.cpp
+//  AUTHOR: Rob Tillaart
+// VERSION: 0.1.13
+// PURPOSE: DHT Temperature & Humidity Sensor library for Arduino
+//     URL: http://arduino.cc/playground/Main/DHTLib
+//
+// HISTORY:
+// 0.1.13 fix negative temperature
+// 0.1.12 support DHT33 and DHT44 initial version
+// 0.1.11 renamed DHTLIB_TIMEOUT
+// 0.1.10 optimized faster WAKEUP + TIMEOUT
+// 0.1.09 optimize size: timeout check + use of mask
+// 0.1.08 added formula for timeout based upon clockspeed
+// 0.1.07 added support for DHT21
+// 0.1.06 minimize footprint (2012-12-27)
+// 0.1.05 fixed negative temperature bug (thanks to Roseman)
+// 0.1.04 improved readability of code using DHTLIB_OK in code
+// 0.1.03 added error values for temp and humidity when read failed
+// 0.1.02 added error codes
+// 0.1.01 added support for Arduino 1.0, fixed typos (31/12/2011)
+// 0.1.0 by Rob Tillaart (01/04/2011)
+//
+// inspired by DHT11 library
+//
+// Released to the public domain
+//
+
+#include "dht.h"
+
+/////////////////////////////////////////////////////
+//
+// PUBLIC
+//
+
+// return values:
+// DHTLIB_OK
+// DHTLIB_ERROR_CHECKSUM
+// DHTLIB_ERROR_TIMEOUT
+int dht::read11(uint8_t pin)
+{
+    // READ VALUES
+    int rv = _readSensor(pin, DHTLIB_DHT11_WAKEUP);
+    if (rv != DHTLIB_OK)
+    {
+        humidity    = DHTLIB_INVALID_VALUE; // invalid value, or is NaN prefered?
+        temperature = DHTLIB_INVALID_VALUE; // invalid value
+        return rv;
+    }
+
+    // CONVERT AND STORE
+    humidity    = bits[0];  // bits[1] == 0;
+    temperature = bits[2];  // bits[3] == 0;
+
+    // TEST CHECKSUM
+    // bits[1] && bits[3] both 0
+    uint8_t sum = bits[0] + bits[2];
+    if (bits[4] != sum) return DHTLIB_ERROR_CHECKSUM;
+
+    return DHTLIB_OK;
+}
+
+
+// return values:
+// DHTLIB_OK
+// DHTLIB_ERROR_CHECKSUM
+// DHTLIB_ERROR_TIMEOUT
+int dht::read(uint8_t pin)
+{
+    // READ VALUES
+    int rv = _readSensor(pin, DHTLIB_DHT_WAKEUP);
+    if (rv != DHTLIB_OK)
+    {
+        humidity    = DHTLIB_INVALID_VALUE;  // invalid value, or is NaN prefered?
+        temperature = DHTLIB_INVALID_VALUE;  // invalid value
+        return rv; // propagate error value
+    }
+
+    // CONVERT AND STORE
+    humidity = word(bits[0], bits[1]) * 0.1;
+    temperature = word(bits[2] & 0x7F, bits[3]) * 0.1;
+    if (bits[2] & 0x80)  // negative temperature
+    {
+        temperature = -temperature;
+    }
+
+    // TEST CHECKSUM
+    uint8_t sum = bits[0] + bits[1] + bits[2] + bits[3];
+    if (bits[4] != sum)
+    {
+        return DHTLIB_ERROR_CHECKSUM;
+    }
+    return DHTLIB_OK;
+}
+
+/////////////////////////////////////////////////////
+//
+// PRIVATE
+//
+
+// return values:
+// DHTLIB_OK
+// DHTLIB_ERROR_TIMEOUT
+int dht::_readSensor(uint8_t pin, uint8_t wakeupDelay)
+{
+    // INIT BUFFERVAR TO RECEIVE DATA
+    uint8_t mask = 128;
+    uint8_t idx = 0;
+
+    // EMPTY BUFFER
+    for (uint8_t i = 0; i < 5; i++) bits[i] = 0;
+
+    // REQUEST SAMPLE
+    pinMode(pin, OUTPUT);
+    digitalWrite(pin, LOW);
+    delay(wakeupDelay);
+    digitalWrite(pin, HIGH);
+    delayMicroseconds(40);
+    pinMode(pin, INPUT);
+
+    // GET ACKNOWLEDGE or TIMEOUT
+    uint16_t loopCnt = DHTLIB_TIMEOUT;
+    while(digitalRead(pin) == LOW)
+    {
+        if (--loopCnt == 0) return DHTLIB_ERROR_TIMEOUT;
+    }
+
+    loopCnt = DHTLIB_TIMEOUT;
+    while(digitalRead(pin) == HIGH)
+    {
+        if (--loopCnt == 0) return DHTLIB_ERROR_TIMEOUT;
+    }
+
+    // READ THE OUTPUT - 40 BITS => 5 BYTES
+    for (uint8_t i = 40; i != 0; i--)
+    {
+        loopCnt = DHTLIB_TIMEOUT;
+        while(digitalRead(pin) == LOW)
+        {
+            if (--loopCnt == 0) return DHTLIB_ERROR_TIMEOUT;
+        }
+
+        uint32_t t = micros();
+
+        loopCnt = DHTLIB_TIMEOUT;
+        while(digitalRead(pin) == HIGH)
+        {
+            if (--loopCnt == 0) return DHTLIB_ERROR_TIMEOUT;
+        }
+
+        if ((micros() - t) > 40)
+        { 
+            bits[idx] |= mask;
+        }
+        mask >>= 1;
+        if (mask == 0)   // next byte?
+        {
+            mask = 128;
+            idx++;
+        }
+    }
+    pinMode(pin, OUTPUT);
+    digitalWrite(pin, HIGH);
+
+    return DHTLIB_OK;
+}
+//
+// END OF FILE
+//

libraries/DHTstable/dht.h

@@ -0,0 +1,63 @@
+//
+//    FILE: dht.h
+//  AUTHOR: Rob Tillaart
+// VERSION: 0.1.13
+// PURPOSE: DHT Temperature & Humidity Sensor library for Arduino
+//     URL: http://arduino.cc/playground/Main/DHTLib
+//
+// HISTORY:
+// see dht.cpp file
+//
+
+#ifndef dht_h
+#define dht_h
+
+#if ARDUINO < 100
+#include <WProgram.h>
+#else
+#include <Arduino.h>
+#endif
+
+#define DHT_LIB_VERSION "0.1.13"
+
+#define DHTLIB_OK                0
+#define DHTLIB_ERROR_CHECKSUM   -1
+#define DHTLIB_ERROR_TIMEOUT    -2
+#define DHTLIB_INVALID_VALUE    -999
+
+#define DHTLIB_DHT11_WAKEUP     18
+#define DHTLIB_DHT_WAKEUP       1
+
+// max timeout is 100usec.
+// For a 16Mhz proc that is max 1600 clock cycles
+// loops using TIMEOUT use at least 4 clock cycli
+// so 100 us takes max 400 loops
+// so by dividing F_CPU by 40000 we "fail" as fast as possible
+#define DHTLIB_TIMEOUT (F_CPU/40000)
+
+class dht
+{
+public:
+    // return values:
+    // DHTLIB_OK
+    // DHTLIB_ERROR_CHECKSUM
+    // DHTLIB_ERROR_TIMEOUT
+    int read11(uint8_t pin);
+    int read(uint8_t pin);
+
+    inline int read21(uint8_t pin) { return read(pin); };
+    inline int read22(uint8_t pin) { return read(pin); };
+    inline int read33(uint8_t pin) { return read(pin); };
+    inline int read44(uint8_t pin) { return read(pin); };
+
+    double humidity;
+    double temperature;
+
+private:
+    uint8_t bits[5];  // buffer to receive data
+    int _readSensor(uint8_t pin, uint8_t wakeupDelay);
+};
+#endif
+//
+// END OF FILE
+//

libraries/DHTstable/readme.txt

@@ -0,0 +1,5 @@
+
+This is the 0.1.13 version of the DHTlib. 
+This version is stable for both ARM and AVR.
+
+You can use most examples from https://github.com/RobTillaart/Arduino/tree/master/libraries/DHTlib/examples