Tasmota/tasmota/xsns_58_dht12.ino

130 lines
3.3 KiB
C++

/*
xsns_58_dht12.ino - DHT12 I2C temperature and humidity sensor support for Tasmota
Copyright (C) 2020 Stefan Oskamp and Theo Arends
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifdef USE_I2C
#ifdef USE_DHT12
/*********************************************************************************************\
* DHT12 - Temperature and Humidity
*
* I2C Address: 0x5C
\*********************************************************************************************/
#define XSNS_58 58
#define XI2C_41 41 // See I2CDEVICES.md
#define DHT12_ADDR 0x5C
struct DHT12 {
float temperature = NAN;
float humidity = NAN;
uint8_t valid = 0;
uint8_t count = 0;
char name[6] = "DHT12";
} Dht12;
bool Dht12Read(void)
{
if (Dht12.valid) { Dht12.valid--; }
Wire.beginTransmission(DHT12_ADDR);
Wire.write(0);
if (Wire.endTransmission() != 0) { return false; }
delay(50);
Wire.requestFrom(DHT12_ADDR, 5);
delay(5);
uint8_t humidity = Wire.read();
uint8_t humidityTenth = Wire.read();
uint8_t temp = Wire.read();
uint8_t tempTenth = Wire.read();
uint8_t checksum = Wire.read();
Dht12.humidity = ConvertHumidity( (float) humidity + (float) humidityTenth/(float) 10.0 );
Dht12.temperature = ConvertTemp( (float) temp + (float) tempTenth/(float) 10.0 );
if (isnan(Dht12.temperature) || isnan(Dht12.humidity)) { return false; }
Dht12.valid = SENSOR_MAX_MISS;
return true;
}
/********************************************************************************************/
void Dht12Detect(void)
{
if (I2cActive(DHT12_ADDR)) { return; }
if (Dht12Read()) {
I2cSetActiveFound(DHT12_ADDR, Dht12.name);
Dht12.count = 1;
}
}
void Dht12EverySecond(void)
{
if (uptime &1) {
// DHT12: 55mS
if (!Dht12Read()) {
AddLogMissed(Dht12.name, Dht12.valid);
}
}
}
void Dht12Show(bool json)
{
if (Dht12.valid) {
TempHumDewShow(json, (0 == tele_period), Dht12.name, Dht12.temperature, Dht12.humidity);
}
}
/*********************************************************************************************\
* Interface
\*********************************************************************************************/
bool Xsns58(uint8_t function)
{
if (!I2cEnabled(XI2C_41)) { return false; }
bool result = false;
if (FUNC_INIT == function) {
Dht12Detect();
}
else if (Dht12.count) {
switch (function) {
case FUNC_EVERY_SECOND:
Dht12EverySecond();
break;
case FUNC_JSON_APPEND:
Dht12Show(1);
break;
#ifdef USE_WEBSERVER
case FUNC_WEB_SENSOR:
Dht12Show(0);
break;
#endif // USE_WEBSERVER
}
}
return result;
}
#endif // USE_DHT12
#endif // USE_I2C