mirror of
https://github.com/adafruit/DHT-sensor-library.git
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documented DHT
This commit is contained in:
Jan Hoffmann
parent
30809d2a6c
commit
dd455428a0
164
DHT.cpp
164
DHT.cpp
@ -1,14 +1,42 @@
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/* DHT library
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MIT license
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written by Adafruit Industries
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/*!
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* @file DHT.cpp
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*
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* @mainpage DHT series of low cost temperature/humidity sensors.
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*
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* @section intro_sec Introduction
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*
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* This is a library for DHT series of low cost temperature/humidity sensors.
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*
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* You must have Adafruit Unified Sensor Library library installed to use this
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* class.
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*
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* Adafruit invests time and resources providing this open source code,
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* please support Adafruit andopen-source hardware by purchasing products
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* from Adafruit!
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*
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* @section author Author
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*
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* Written by Adafruit Industries.
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*
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* @section license License
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*
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* MIT license, all text above must be included in any redistribution
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*/
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#include "DHT.h"
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#define MIN_INTERVAL 2000
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#define TIMEOUT -1
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#define MIN_INTERVAL 2000 /**< min interval value */
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#define TIMEOUT -1 /**< timeout on */
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/*!
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* @brief Instantiates a new DHT class
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* @param pin
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* pin number that sensor is connected
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* @param type
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* type of sensor
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* @param count
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* number of sensors
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*/
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DHT::DHT(uint8_t pin, uint8_t type, uint8_t count) {
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_pin = pin;
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_type = type;
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@ -16,14 +44,19 @@ DHT::DHT(uint8_t pin, uint8_t type, uint8_t count) {
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_bit = digitalPinToBitMask(pin);
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_port = digitalPinToPort(pin);
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#endif
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_maxcycles = microsecondsToClockCycles(1000); // 1 millisecond timeout for
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_maxcycles =
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microsecondsToClockCycles(1000); // 1 millisecond timeout for
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// reading pulses from DHT sensor.
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// Note that count is now ignored as the DHT reading algorithm adjusts itself
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// based on the speed of the processor.
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}
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// Optionally pass pull-up time (in microseconds) before DHT reading starts.
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// Default is 55 (see function declaration in DHT.h).
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/*!
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* @brief Setup sensor pins and set pull timings
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* @param usec
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* Optionally pass pull-up time (in microseconds) before DHT reading
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*starts. Default is 55 (see function declaration in DHT.h).
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*/
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void DHT::begin(uint8_t usec) {
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// set up the pins!
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pinMode(_pin, INPUT_PULLUP);
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@ -31,11 +64,21 @@ void DHT::begin(uint8_t usec) {
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// >= MIN_INTERVAL right away. Note that this assignment wraps around,
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// but so will the subtraction.
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_lastreadtime = millis() - MIN_INTERVAL;
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DEBUG_PRINT("DHT max clock cycles: "); DEBUG_PRINTLN(_maxcycles, DEC);
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DEBUG_PRINT("DHT max clock cycles: ");
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DEBUG_PRINTLN(_maxcycles, DEC);
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pullTime = usec;
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}
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//boolean S == Scale. True == Fahrenheit; False == Celcius
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/*!
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* @brief Read temperature
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* @param S
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* Scale. Boolean value:
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* - true = Fahrenheit
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* - false = Celcius
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* @param force
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* true if in force mode
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* @return Temperature value in selected scale
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*/
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float DHT::readTemperature(bool S, bool force) {
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float f = NAN;
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@ -77,14 +120,28 @@ float DHT::readTemperature(bool S, bool force) {
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return f;
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}
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float DHT::convertCtoF(float c) {
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return c * 1.8 + 32;
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}
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/*!
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* @brief Converts Celcius to Fahrenheit
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* @param c
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* value in Celcius
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* @return float value in Fahrenheit
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*/
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float DHT::convertCtoF(float c) { return c * 1.8 + 32; }
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float DHT::convertFtoC(float f) {
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return (f - 32) * 0.55555;
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}
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/*!
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* @brief Converts Fahrenheit to Celcius
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* @param f
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* value in Fahrenheit
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* @return float value in Celcius
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*/
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float DHT::convertFtoC(float f) { return (f - 32) * 0.55555; }
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/*!
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* @brief Read Humidity
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* @param force
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* force read mode
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* @return float value - humidity in percent
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*/
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float DHT::readHumidity(bool force) {
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float f = NAN;
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if (read(force)) {
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@ -103,29 +160,44 @@ float DHT::readHumidity(bool force) {
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return f;
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}
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//boolean isFahrenheit: True == Fahrenheit; False == Celcius
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/*!
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* @brief Compute Heat Index
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* Simplified version that reads temp and humidity from sensor
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* @param isFahrenheit
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* true if fahrenheit, false if celcius (default
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*true)
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* @return float heat index
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*/
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float DHT::computeHeatIndex(bool isFahrenheit) {
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float hi = computeHeatIndex(readTemperature(isFahrenheit), readHumidity(),
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isFahrenheit);
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return hi;
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}
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//boolean isFahrenheit: True == Fahrenheit; False == Celcius
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/*!
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* @brief Compute Heat Index
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* Using both Rothfusz and Steadman's equations
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* (http://www.wpc.ncep.noaa.gov/html/heatindex_equation.shtml)
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* @param temperature
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* temperature in selected scale
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* @param percentHumidity
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* humidity in percent
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* @param isFahrenheit
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* true if fahrenheit, false if celcius
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* @return float heat index
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*/
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float DHT::computeHeatIndex(float temperature, float percentHumidity,
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bool isFahrenheit) {
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// Using both Rothfusz and Steadman's equations
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// http://www.wpc.ncep.noaa.gov/html/heatindex_equation.shtml
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float hi;
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if (!isFahrenheit)
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temperature = convertCtoF(temperature);
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hi = 0.5 * (temperature + 61.0 + ((temperature - 68.0) * 1.2) + (percentHumidity * 0.094));
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hi = 0.5 * (temperature + 61.0 + ((temperature - 68.0) * 1.2) +
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(percentHumidity * 0.094));
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if (hi > 79) {
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hi = -42.379 +
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2.04901523 * temperature +
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10.14333127 * percentHumidity +
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hi = -42.379 + 2.04901523 * temperature + 10.14333127 * percentHumidity +
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-0.22475541 * temperature * percentHumidity +
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-0.00683783 * pow(temperature, 2) +
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-0.05481717 * pow(percentHumidity, 2) +
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@ -133,16 +205,26 @@ float DHT::computeHeatIndex(float temperature, float percentHumidity,
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0.00085282 * temperature * pow(percentHumidity, 2) +
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-0.00000199 * pow(temperature, 2) * pow(percentHumidity, 2);
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if((percentHumidity < 13) && (temperature >= 80.0) && (temperature <= 112.0))
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hi -= ((13.0 - percentHumidity) * 0.25) * sqrt((17.0 - abs(temperature - 95.0)) * 0.05882);
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if ((percentHumidity < 13) && (temperature >= 80.0) &&
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(temperature <= 112.0))
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hi -= ((13.0 - percentHumidity) * 0.25) *
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sqrt((17.0 - abs(temperature - 95.0)) * 0.05882);
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else if((percentHumidity > 85.0) && (temperature >= 80.0) && (temperature <= 87.0))
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else if ((percentHumidity > 85.0) && (temperature >= 80.0) &&
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(temperature <= 87.0))
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hi += ((percentHumidity - 85.0) * 0.1) * ((87.0 - temperature) * 0.2);
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}
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return isFahrenheit ? hi : convertFtoC(hi);
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}
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/*!
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* @brief Read value from sensor or return last one from less than two
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*seconds.
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* @param force
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* true if using force mode
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* @return float value
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*/
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bool DHT::read(bool force) {
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// Check if sensor was read less than two seconds ago and return early
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// to use last reading.
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@ -214,8 +296,8 @@ bool DHT::read(bool force) {
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// then it's a 1. We measure the cycle count of the initial 50us low pulse
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// and use that to compare to the cycle count of the high pulse to determine
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// if the bit is a 0 (high state cycle count < low state cycle count), or a
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// 1 (high state cycle count > low state cycle count). Note that for speed all
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// the pulses are read into a array and then examined in a later step.
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// 1 (high state cycle count > low state cycle count). Note that for speed
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// all the pulses are read into a array and then examined in a later step.
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for (int i = 0; i < 80; i += 2) {
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cycles[i] = expectPulse(LOW);
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cycles[i + 1] = expectPulse(HIGH);
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@ -244,19 +326,23 @@ bool DHT::read(bool force) {
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}
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DEBUG_PRINTLN(F("Received from DHT:"));
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DEBUG_PRINT(data[0], HEX); DEBUG_PRINT(F(", "));
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DEBUG_PRINT(data[1], HEX); DEBUG_PRINT(F(", "));
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DEBUG_PRINT(data[2], HEX); DEBUG_PRINT(F(", "));
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DEBUG_PRINT(data[3], HEX); DEBUG_PRINT(F(", "));
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DEBUG_PRINT(data[4], HEX); DEBUG_PRINT(F(" =? "));
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DEBUG_PRINT(data[0], HEX);
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DEBUG_PRINT(F(", "));
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DEBUG_PRINT(data[1], HEX);
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DEBUG_PRINT(F(", "));
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DEBUG_PRINT(data[2], HEX);
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DEBUG_PRINT(F(", "));
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DEBUG_PRINT(data[3], HEX);
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DEBUG_PRINT(F(", "));
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DEBUG_PRINT(data[4], HEX);
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DEBUG_PRINT(F(" =? "));
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DEBUG_PRINTLN((data[0] + data[1] + data[2] + data[3]) & 0xFF, HEX);
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// Check we read 40 bits and that the checksum matches.
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if (data[4] == ((data[0] + data[1] + data[2] + data[3]) & 0xFF)) {
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_lastresult = true;
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return _lastresult;
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}
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else {
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} else {
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DEBUG_PRINTLN(F("DHT checksum failure!"));
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_lastresult = false;
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return _lastresult;
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@ -285,8 +371,8 @@ uint32_t DHT::expectPulse(bool level) {
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return TIMEOUT; // Exceeded timeout, fail.
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}
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}
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// Otherwise fall back to using digitalRead (this seems to be necessary on ESP8266
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// right now, perhaps bugs in direct port access functions?).
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// Otherwise fall back to using digitalRead (this seems to be necessary on
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// ESP8266 right now, perhaps bugs in direct port access functions?).
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#else
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while (digitalRead(_pin) == level) {
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if (count++ >= _maxcycles) {
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55
DHT.h
55
DHT.h
@ -1,41 +1,49 @@
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/* DHT library
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MIT license
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written by Adafruit Industries
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/*!
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* @file DHT.h
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*
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* This is a library for DHT series of low cost temperature/humidity sensors.
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*
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* You must have Adafruit Unified Sensor Library library installed to use this class.
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*
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* Adafruit invests time and resources providing this open source code,
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* please support Adafruit andopen-source hardware by purchasing products
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* from Adafruit!
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*
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* Written by Adafruit Industries.
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*
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* MIT license, all text above must be included in any redistribution
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*/
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#ifndef DHT_H
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#define DHT_H
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#if ARDUINO >= 100
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#include "Arduino.h"
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#else
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#include "WProgram.h"
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#endif
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// Uncomment to enable printing out nice debug messages.
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/* Uncomment to enable printing out nice debug messages. */
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//#define DHT_DEBUG
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// Define where debug output will be printed.
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#define DEBUG_PRINTER Serial
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// Setup debug printing macros.
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#define DEBUG_PRINTER Serial /**< Define where debug output will be printed. */
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/* Setup debug printing macros. */
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#ifdef DHT_DEBUG
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#define DEBUG_PRINT(...) { DEBUG_PRINTER.print(__VA_ARGS__); }
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#define DEBUG_PRINTLN(...) { DEBUG_PRINTER.println(__VA_ARGS__); }
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#else
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#define DEBUG_PRINT(...) {}
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#define DEBUG_PRINTLN(...) {}
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#define DEBUG_PRINT(...) {} /**< Debug Print Placeholder if Debug is disabled */
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#define DEBUG_PRINTLN(...) {} /**< Debug Print Line Placeholder if Debug is disabled */
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#endif
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// Define types of sensors.
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#define DHT11 11
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#define DHT12 12
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#define DHT22 22
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#define DHT21 21
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#define AM2301 21
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/* Define types of sensors. */
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#define DHT11 11 /**< DHT TYPE 11 */
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#define DHT12 12 /**< DHY TYPE 12 */
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#define DHT22 22 /**< DHT TYPE 22 */
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#define DHT21 21 /**< DHT TYPE 21 */
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#define AM2301 21 /**< AM2301 */
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/*!
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* @brief Class that stores state and functions for DHT
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*/
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class DHT {
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public:
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DHT(uint8_t pin, uint8_t type, uint8_t count=6);
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@ -64,6 +72,9 @@ class DHT {
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};
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/*!
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* @brief Class that defines Interrupt Lock Avaiability
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*/
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class InterruptLock {
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public:
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InterruptLock() {
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77
DHT_U.h
77
DHT_U.h
@ -1,37 +1,56 @@
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// DHT Temperature & Humidity Unified Sensor Library
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// Copyright (c) 2014 Adafruit Industries
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// Author: Tony DiCola
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/*!
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* @file DHT_U.h
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*
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* DHT Temperature & Humidity Unified Sensor Library<Paste>
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*
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* Adafruit invests time and resources providing this open source code,
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* please support Adafruit andopen-source hardware by purchasing products
|
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* from Adafruit!
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*
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* Written by Tony DiCola (Adafruit Industries) 2014.
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*
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* MIT license, all text above must be included in any redistribution
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
|
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* of this software and associated documentation files (the "Software"), to
|
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* deal in the Software without restriction, including without limitation the
|
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* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
|
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* sell copies of the Software, and to permit persons to whom the Software is
|
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* furnished to do so, subject to the following conditions:
|
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*
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* The above copyright notice and this permission notice shall be included in
|
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
|
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
|
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* IN THE SOFTWARE.
|
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*/
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// Permission is hereby granted, free of charge, to any person obtaining a copy
|
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// of this software and associated documentation files (the "Software"), to deal
|
||||
// in the Software without restriction, including without limitation the rights
|
||||
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
|
||||
// copies of the Software, and to permit persons to whom the Software is
|
||||
// furnished to do so, subject to the following conditions:
|
||||
|
||||
// The above copyright notice and this permission notice shall be included in all
|
||||
// copies or substantial portions of the Software.
|
||||
|
||||
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
||||
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
||||
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
|
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// SOFTWARE.
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#ifndef DHT_U_H
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#define DHT_U_H
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#include <Adafruit_Sensor.h>
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#include <DHT.h>
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#define DHT_SENSOR_VERSION 1
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#define DHT_SENSOR_VERSION 1 /**< Sensor Version */
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/*!
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* @brief Class that stores state and functions for interacting with
|
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* DHT_Unified.
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*/
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class DHT_Unified {
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public:
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DHT_Unified(uint8_t pin, uint8_t type, uint8_t count=6, int32_t tempSensorId=-1, int32_t humiditySensorId=-1);
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DHT_Unified(uint8_t pin, uint8_t type, uint8_t count = 6,
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int32_t tempSensorId = -1, int32_t humiditySensorId = -1);
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void begin();
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/*!
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* @brief Class that stores state and functions about Temperature
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*/
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class Temperature : public Adafruit_Sensor {
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public:
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Temperature(DHT_Unified *parent, int32_t id);
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@ -41,9 +60,11 @@ public:
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private:
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DHT_Unified *_parent;
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int32_t _id;
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};
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/*!
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* @brief Class that stores state and functions about Humidity
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*/
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class Humidity : public Adafruit_Sensor {
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public:
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Humidity(DHT_Unified *parent, int32_t id);
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@ -53,16 +74,11 @@ public:
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private:
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DHT_Unified *_parent;
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int32_t _id;
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};
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Temperature temperature() {
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return _temp;
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}
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Temperature temperature() { return _temp; }
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Humidity humidity() {
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return _humidity;
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}
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Humidity humidity() { return _humidity; }
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private:
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DHT _dht;
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@ -72,7 +88,6 @@ private:
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|
||||
void setName(sensor_t *sensor);
|
||||
void setMinDelay(sensor_t *sensor);
|
||||
|
||||
};
|
||||
|
||||
#endif
|
||||
|
||||
Loading…
Reference in New Issue
Block a user