/* xsns_38_az7798.ino - AZ_Instrument 7798 CO2/temperature/humidity meter support for Tasmota Copyright (C) 2021 adebeun 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(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(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(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(LOG_LEVEL_DEBUG, PSTR(D_LOG_DEBUG "AZ7798 error first delimiter")); return; } i++; // advance to start of CO2 if(az_response[i] != 'C') { AddLog(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(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); #ifdef USE_LIGHT LightSetSignal(CO2_LOW, CO2_HIGH, az_co2); #endif // USE_LIGHT i += 3; // advance to second delimiter if(az_response[i] != ':') { AddLog(LOG_LEVEL_DEBUG, PSTR(D_LOG_DEBUG "AZ7798 error second delimiter")); return; } i++; // advance to start of humidity if(az_response[i] != 'H') { AddLog(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(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(LOG_LEVEL_DEBUG, PSTR(D_LOG_DEBUG "AZ7798 clock updated")); } else { az_clock_update--; } } /*********************************************************************************************/ void AzInit(void) { az_type = 0; if (PinUsed(GPIO_AZ_RXD) && PinUsed(GPIO_AZ_TXD)) { AzSerial = new TasmotaSerial(Pin(GPIO_AZ_RXD), Pin(GPIO_AZ_TXD), 1); if (AzSerial->begin(9600)) { if (AzSerial->hardwareSerial()) { ClaimSerial(); } #ifdef ESP32 AddLog(LOG_LEVEL_DEBUG, PSTR("AZ7: Serial UART%d"), AzSerial->getUart()); #endif 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 == TasmotaGlobal.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(uint32_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