/*
xsns_38_az7798.ino - AZ_Instrument 7798 CO2/temperature/humidity meter support for Tasmota
Copyright (C) 2020 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 .
*/
#ifdef USE_AZ7798
#define XSNS_38 38
/*********************************************************************************************\
* CO2, temperature and humidity meter and data logger
* Known by different names (brief survey 2018-12-16):
* - AZ-Instrument 7798 (http://www.az-instrument.com.tw)
* - co2meter.com AZ-0004
* - Extech CO200
* - BES CO7788 (https://www.aliexpress.com)
* - AZ CO87 (https://www.aliexpress.com)
* - no doubt there are more ...
*
* Hardware Serial will be selected if GPIO1 = [AZ Tx] and GPIO3 = [AZ Rx]
*
* Inside the meter, the serial comms wire with the red stripe goes to GPIO1.
* The other one therefore to GPIO3.
* WeMos D1 Mini is powered from the incoming 5V.
*
* This implementation was derived from xsns_15_mhz19.ino from
* Tasmota-6.3.0 by Arthur de Beun.
*
* The serial comms protocol is not publicly documented, that I could find.
* The info below was obtained by reverse-engineering.
* Port settings: 9600 8N1
* The suppied USB interface has a CP20x USB-serial bridge.
* The 3-way, 2.5mm jack has tip=RxD, middle=TxD and base=0V
* The TxD output swing is 3V3.
*
* There is never a space before the 0x0d, but the other spaces are there.
*
* serial number / ID
* request: I 0x0d
* response: i 12345678 7798V3.4 0x0d
*
* log info
* request: M 0x0d
* response: m 45 1 C 1af4 0cf4 0x0d
*
* 45 = number of records, but there are only 15 lines of 3 values each)
* 1 = sample rate in seconds
* C = celcius, F
* 1af4 0cf4 = seconds since 2000-01-01 00:00:00
*
* start time 2014-04-30 19:35:16
* end time 2014-04-30 19:35:30
*
* download log data
* request: D 0x0d
* response: m 45 1 C 1af4 0cf4 0x0d
* d 174 955 698 0x0d
* 174 = temp in [C * 10]
* 955 = CO2 [ppm]
* 698 = RH in [% * 10]
* d 174 990 694 0x0d
* ...
* d 173 929 654 0x0d
*
* 15 lines in total, 1 second apart
*
* Sync datalogger time with PC
* request: C 452295746 0x0d
* response: > 0x0d
*
* 452295746 = seconds since 2000-01-01 00:00:00
*
* Identifier:
* request: J -------- 1 0x0d
*
* the characters (dashes) in the above become the first part of the response to the I command (12345678 above)
*
* Set sample rate
* request: S 10 0x0d
* response: m 12 10 C 1af5 7be1 0x0d
*
* Other characters that seem to give a response:
* A responds with >
* so is similar to the response to C, so other characters may be required
* A is the beep alarm perhaps?
* parameters would be CO2 level and on/off, as per front panel P1.3 setting?
*
* L responds with >
* L perhaps sets the limits for the good and normal levels (P1.1 and P1.2)?
*
* Q responds with >
* Q is reset maybe (P4.1)?
*
* : responds with : T19.9C:C2167ppm:H57.4%
* This one gives the current readings.
\*********************************************************************************************/
#include
#ifndef CO2_LOW
#define CO2_LOW 800 // Below this CO2 value show green light
#endif
#ifndef CO2_HIGH
#define CO2_HIGH 1200 // Above this CO2 value show red light
#endif
#define AZ_READ_TIMEOUT 400 // Must be way less than 1000 but enough to read 25 bytes at 9600 bps
#define AZ_CLOCK_UPDATE_INTERVAL (24UL * 60 * 60) // periodically update clock display (24 hours)
#define AZ_EPOCH (946684800UL) // 2000-01-01 00:00:00
TasmotaSerial *AzSerial;
const char ktype[] = "AZ7798";
uint8_t az_type = 1;
uint16_t az_co2 = 0;
double az_temperature = 0;
double az_humidity = 0;
uint8_t az_received = 0;
uint8_t az_state = 0;
unsigned long az_clock_update = 10; // timer for periodically updating clock display
/*********************************************************************************************/
void AzEverySecond(void)
{
unsigned long start = millis();
az_state++;
if (5 == az_state) { // every 5 seconds
az_state = 0;
AzSerial->flush(); // sync reception
AzSerial->write(":\r", 2);
az_received = 0;
uint8_t az_response[32];
uint8_t counter = 0;
uint8_t i, j;
uint8_t response_substr[16];
do {
if (AzSerial->available() > 0) {
az_response[counter] = AzSerial->read();
if(az_response[counter] == 0x0d) { az_received = 1; }
counter++;
} else {
delay(5);
}
} while(((millis() - start) < AZ_READ_TIMEOUT) && (counter < sizeof(az_response)) && !az_received);
AddLogBuffer(LOG_LEVEL_DEBUG_MORE, az_response, counter);
if (!az_received) {
AddLog_P(LOG_LEVEL_DEBUG, PSTR(D_LOG_DEBUG "AZ7798 comms timeout"));
return;
}
i = 0;
while((az_response[i] != 'T') && (i < counter)) {i++;} // find the start of response
if(az_response[i] != 'T') {
AddLog_P(LOG_LEVEL_DEBUG, PSTR(D_LOG_DEBUG "AZ7798 failed to find start of response"));
return;
}
i++; // advance to start of temperature value
j = 0;
// find the end of temperature
while((az_response[i] != 'C') && (az_response[i] != 'F') && (i < counter)) {
response_substr[j++] = az_response[i++];
}
if((az_response[i] != 'C') && (az_response[i] != 'F')){
AddLog_P(LOG_LEVEL_DEBUG, PSTR(D_LOG_DEBUG "AZ7798 failed to find end of temperature"));
return;
}
response_substr[j] = 0; // add null terminator
az_temperature = CharToFloat((char*)response_substr); // units (C or F) depends on meter setting
if(az_response[i] == 'C') { // meter transmits in degC
az_temperature = ConvertTemp((float)az_temperature); // convert to degF, depending on settings
} else { // meter transmits in degF
az_temperature = ConvertTemp((az_temperature - 32) / 1.8); // convert to degC and then C or F depending on setting
}
i++; // advance to first delimiter
if(az_response[i] != ':') {
AddLog_P(LOG_LEVEL_DEBUG, PSTR(D_LOG_DEBUG "AZ7798 error first delimiter"));
return;
}
i++; // advance to start of CO2
if(az_response[i] != 'C') {
AddLog_P(LOG_LEVEL_DEBUG, PSTR(D_LOG_DEBUG "AZ7798 error start of CO2"));
return;
}
i++; // advance to start of CO2 value
j = 0;
// find the end of CO2
while((az_response[i] != 'p') && (i < counter)) {
response_substr[j++] = az_response[i++];
}
if(az_response[i] != 'p') {
AddLog_P(LOG_LEVEL_DEBUG, PSTR(D_LOG_DEBUG "AZ7798 failed to find end of CO2"));
return;
}
response_substr[j] = 0; // add null terminator
az_co2 = atoi((char*)response_substr);
LightSetSignal(CO2_LOW, CO2_HIGH, az_co2);
i += 3; // advance to second delimiter
if(az_response[i] != ':') {
AddLog_P(LOG_LEVEL_DEBUG, PSTR(D_LOG_DEBUG "AZ7798 error second delimiter"));
return;
}
i++; // advance to start of humidity
if(az_response[i] != 'H') {
AddLog_P(LOG_LEVEL_DEBUG, PSTR(D_LOG_DEBUG "AZ7798 error start of humidity"));
return;
}
i++; // advance to start of humidity value
j = 0;
// find the end of humidity
while((az_response[i] != '%') && (i < counter)) {
response_substr[j++] = az_response[i++];
}
if(az_response[i] != '%') {
AddLog_P(LOG_LEVEL_DEBUG, PSTR(D_LOG_DEBUG "AZ7798 failed to find end of humidity"));
return;
}
response_substr[j] = 0; // add null terminator
az_humidity = ConvertHumidity(CharToFloat((char*)response_substr));
}
// update the clock from network time
if ((az_clock_update == 0) && (LocalTime() > AZ_EPOCH)) {
char tmpString[16];
sprintf(tmpString, "C %d\r", (int)(LocalTime() - AZ_EPOCH));
AzSerial->write(tmpString);
// discard the response
do {
if (AzSerial->available() > 0) {
if(AzSerial->read() == 0x0d) { break; }
} else {
delay(5);
}
} while(((millis() - start) < AZ_READ_TIMEOUT));
az_clock_update = AZ_CLOCK_UPDATE_INTERVAL;
AddLog_P(LOG_LEVEL_DEBUG, PSTR(D_LOG_DEBUG "AZ7798 clock updated"));
} else {
az_clock_update--;
}
}
/*********************************************************************************************/
void AzInit(void)
{
az_type = 0;
if ((pin[GPIO_AZ_RXD] < 99) && (pin[GPIO_AZ_TXD] < 99)) {
AzSerial = new TasmotaSerial(pin[GPIO_AZ_RXD], pin[GPIO_AZ_TXD], 1);
if (AzSerial->begin(9600)) {
if (AzSerial->hardwareSerial()) { ClaimSerial(); }
az_type = 1;
}
}
}
void AzShow(bool json)
{
if (json) {
ResponseAppend_P(PSTR(",\"%s\":{\"" D_JSON_CO2 "\":%d,"), ktype, az_co2);
ResponseAppendTHD(az_temperature, az_humidity);
ResponseJsonEnd();
#ifdef USE_DOMOTICZ
if (0 == tele_period) DomoticzSensor(DZ_AIRQUALITY, az_co2);
#endif // USE_DOMOTICZ
#ifdef USE_WEBSERVER
} else {
WSContentSend_PD(HTTP_SNS_CO2, ktype, az_co2);
WSContentSend_THD(ktype, az_temperature, az_humidity);
#endif // USE_WEBSERVER
}
}
/*********************************************************************************************\
* Interface
\*********************************************************************************************/
bool Xsns38(uint8_t function)
{
bool result = false;
if(az_type){
switch (function) {
case FUNC_INIT:
AzInit();
break;
case FUNC_EVERY_SECOND:
AzEverySecond();
break;
case FUNC_JSON_APPEND:
AzShow(1);
break;
#ifdef USE_WEBSERVER
case FUNC_WEB_SENSOR:
AzShow(0);
break;
#endif // USE_WEBSERVER
}
}
return result;
}
#endif // USE_AZ7798