You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
254 lines
7.3 KiB
254 lines
7.3 KiB
// -----------------------------------------------------------------------------
|
|
// DHTXX Sensor
|
|
// Copyright (C) 2017-2019 by Xose Pérez <xose dot perez at gmail dot com>
|
|
// -----------------------------------------------------------------------------
|
|
|
|
#if SENSOR_SUPPORT && DHT_SUPPORT
|
|
|
|
#pragma once
|
|
|
|
#include "Arduino.h"
|
|
#include "BaseSensor.h"
|
|
|
|
#define DHT_MAX_DATA 5
|
|
#define DHT_MAX_ERRORS 5
|
|
#define DHT_MIN_INTERVAL 2000
|
|
|
|
#define DHT_CHIP_DHT11 11
|
|
#define DHT_CHIP_DHT12 12
|
|
#define DHT_CHIP_DHT22 22
|
|
#define DHT_CHIP_DHT21 21
|
|
#define DHT_CHIP_AM2301 21
|
|
|
|
class DHTSensor : public BaseSensor {
|
|
|
|
public:
|
|
|
|
// ---------------------------------------------------------------------
|
|
// Public
|
|
// ---------------------------------------------------------------------
|
|
|
|
DHTSensor(): BaseSensor() {
|
|
_count = 2;
|
|
_sensor_id = SENSOR_DHTXX_ID;
|
|
}
|
|
|
|
~DHTSensor() {
|
|
if (_previous != GPIO_NONE) gpioReleaseLock(_previous);
|
|
}
|
|
|
|
// ---------------------------------------------------------------------
|
|
|
|
void setGPIO(unsigned char gpio) {
|
|
_gpio = gpio;
|
|
}
|
|
|
|
void setType(unsigned char type) {
|
|
_type = type;
|
|
}
|
|
|
|
// ---------------------------------------------------------------------
|
|
|
|
unsigned char getGPIO() {
|
|
return _gpio;
|
|
}
|
|
|
|
unsigned char getType() {
|
|
return _type;
|
|
}
|
|
|
|
// ---------------------------------------------------------------------
|
|
// Sensor API
|
|
// ---------------------------------------------------------------------
|
|
|
|
// Initialization method, must be idempotent
|
|
void begin() {
|
|
|
|
_count = 0;
|
|
|
|
// Manage GPIO lock
|
|
if (_previous != GPIO_NONE) gpioReleaseLock(_previous);
|
|
_previous = GPIO_NONE;
|
|
if (!gpioGetLock(_gpio)) {
|
|
_error = SENSOR_ERROR_GPIO_USED;
|
|
return;
|
|
}
|
|
_previous = _gpio;
|
|
|
|
_count = 2;
|
|
_ready = true;
|
|
|
|
}
|
|
|
|
// Pre-read hook (usually to populate registers with up-to-date data)
|
|
void pre() {
|
|
_error = SENSOR_ERROR_OK;
|
|
_read();
|
|
}
|
|
|
|
// Descriptive name of the sensor
|
|
String description() {
|
|
char buffer[20];
|
|
snprintf(buffer, sizeof(buffer), "DHT%d @ GPIO%d", _type, _gpio);
|
|
return String(buffer);
|
|
}
|
|
|
|
// Descriptive name of the slot # index
|
|
String slot(unsigned char index) {
|
|
return description();
|
|
};
|
|
|
|
// Address of the sensor (it could be the GPIO or I2C address)
|
|
String address(unsigned char index) {
|
|
return String(_gpio);
|
|
}
|
|
|
|
// Type for slot # index
|
|
unsigned char type(unsigned char index) {
|
|
if (index == 0) return MAGNITUDE_TEMPERATURE;
|
|
if (index == 1) return MAGNITUDE_HUMIDITY;
|
|
return MAGNITUDE_NONE;
|
|
}
|
|
|
|
// Current value for slot # index
|
|
double value(unsigned char index) {
|
|
if (index == 0) return _temperature;
|
|
if (index == 1) return _humidity;
|
|
return 0;
|
|
}
|
|
|
|
protected:
|
|
|
|
// ---------------------------------------------------------------------
|
|
// Protected
|
|
// ---------------------------------------------------------------------
|
|
|
|
void _read() {
|
|
|
|
if ((_last_ok > 0) && (millis() - _last_ok < DHT_MIN_INTERVAL)) {
|
|
_error = SENSOR_ERROR_OK;
|
|
return;
|
|
}
|
|
|
|
unsigned long low = 0;
|
|
unsigned long high = 0;
|
|
|
|
unsigned char dhtData[DHT_MAX_DATA] = {0};
|
|
unsigned char byteInx = 0;
|
|
unsigned char bitInx = 7;
|
|
|
|
pinMode(_gpio, OUTPUT);
|
|
|
|
// Send start signal to DHT sensor
|
|
if (++_errors > DHT_MAX_ERRORS) {
|
|
_errors = 0;
|
|
digitalWrite(_gpio, HIGH);
|
|
nice_delay(250);
|
|
}
|
|
noInterrupts();
|
|
digitalWrite(_gpio, LOW);
|
|
if ((_type == DHT_CHIP_DHT11) || (_type == DHT_CHIP_DHT12)) {
|
|
nice_delay(20);
|
|
} else {
|
|
delayMicroseconds(1100);
|
|
}
|
|
digitalWrite(_gpio, HIGH);
|
|
delayMicroseconds(40);
|
|
pinMode(_gpio, INPUT_PULLUP);
|
|
delayMicroseconds(10);
|
|
|
|
// No errors, read the 40 data bits
|
|
for( int k = 0; k < 41; k++ ) {
|
|
|
|
// Starts new data transmission with >50us low signal
|
|
low = _signal(100, LOW);
|
|
if (low == 0) {
|
|
_error = SENSOR_ERROR_TIMEOUT;
|
|
return;
|
|
}
|
|
|
|
// Check to see if after >70us rx data is a 0 or a 1
|
|
high = _signal(100, HIGH);
|
|
if (high == 0) {
|
|
_error = SENSOR_ERROR_TIMEOUT;
|
|
return;
|
|
}
|
|
|
|
// Skip the first bit
|
|
if (k == 0) continue;
|
|
|
|
// add the current read to the output data
|
|
// since all dhtData array where set to 0 at the start,
|
|
// only look for "1" (>28us us)
|
|
if (high > low) dhtData[byteInx] |= (1 << bitInx);
|
|
|
|
// index to next byte
|
|
if (bitInx == 0) {
|
|
bitInx = 7;
|
|
++byteInx;
|
|
} else {
|
|
--bitInx;
|
|
}
|
|
|
|
}
|
|
|
|
interrupts();
|
|
|
|
// Verify checksum
|
|
if (dhtData[4] != ((dhtData[0] + dhtData[1] + dhtData[2] + dhtData[3]) & 0xFF)) {
|
|
_error = SENSOR_ERROR_CRC;
|
|
return;
|
|
}
|
|
|
|
// Get humidity from Data[0] and Data[1]
|
|
if (_type == DHT_CHIP_DHT11) {
|
|
_humidity = dhtData[0];
|
|
} else if (_type == DHT_CHIP_DHT12) {
|
|
_humidity = dhtData[0];
|
|
_humidity += dhtData[1] * 0.1;
|
|
} else {
|
|
_humidity = dhtData[0] * 256 + dhtData[1];
|
|
_humidity /= 10;
|
|
}
|
|
|
|
// Get temp from Data[2] and Data[3]
|
|
if (_type == DHT_CHIP_DHT11) {
|
|
_temperature = dhtData[2];
|
|
} else if (_type == DHT_CHIP_DHT12) {
|
|
_temperature = (dhtData[2] & 0x7F);
|
|
_temperature += dhtData[3] * 0.1;
|
|
if (dhtData[2] & 0x80) _temperature *= -1;
|
|
} else {
|
|
_temperature = (dhtData[2] & 0x7F) * 256 + dhtData[3];
|
|
_temperature /= 10;
|
|
if (dhtData[2] & 0x80) _temperature *= -1;
|
|
}
|
|
|
|
_last_ok = millis();
|
|
_errors = 0;
|
|
_error = SENSOR_ERROR_OK;
|
|
|
|
}
|
|
|
|
unsigned long _signal(unsigned long usTimeOut, bool state) {
|
|
unsigned long uSec = 1;
|
|
while (digitalRead(_gpio) == state) {
|
|
if (++uSec > usTimeOut) return 0;
|
|
delayMicroseconds(1);
|
|
}
|
|
return uSec;
|
|
}
|
|
|
|
unsigned char _gpio = GPIO_NONE;
|
|
unsigned char _previous = GPIO_NONE;
|
|
unsigned char _type = DHT_CHIP_DHT22;
|
|
|
|
unsigned long _last_ok = 0;
|
|
unsigned char _errors = 0;
|
|
|
|
double _temperature = 0;
|
|
double _humidity = 0;
|
|
|
|
};
|
|
|
|
#endif // SENSOR_SUPPORT && DHT_SUPPORT
|