Sensor Temperature and Humidity AHT21

[Haui74]

Good morning! 🙂
Has anyone got the AHT21 sensor integrated into Tasmota yet? Tasmota finds 0x38 during the I2C scan, but I don't see measurements (I2C driver 43 is also active).

[barbudor]

Did you self compiled or using a rebuild binary?
It looks like the driver 43 can be compiled either for AHT1x or AHT2x but still report as driver 43.
Confusing coding decision

I can't tell for sure that compiling for AHT2x will work with AHT21 as only AHT20 is referenced in the doc and code but at least I wouldn't expect driver 43 to work if compiled as USE_AHT1x.

Requires

#ifdef USE_AHT1x
#undef USE_AHT1x
#endif
#ifndef USE_AHT2x
#define USE_AHT2x
#endif 

[Haui74]

Its self compiled, i used "Sensor"+ use_AHT2x.

0:00:00.001 HDW: ESP8266EX
00:00:00.050 CFG: Loaded from flash at F7, Count 16
00:00:00.055 QPC: Count 1
00:00:00.077 Project tasmota - Tasmota Version 13.2.0.2(sensors)-2_7_4_9(2023-12-04T08:43:29)
00:00:00.256 I2C: EN16X found at 0x53
00:00:00.800 WIF: Connecting to AP1 Hauis Channel 3 BSSId EC:41:18:EB:E5:09 in mode 11n as tasmota-6D1253-4691...
00:00:03.777 WIF: Connected
00:00:04.030 HTP: Web server active on tasmota-6D1253-4691 with IP address 192.168.0.88
08:44:56.036 RSL: INFO1 = {"Info1":{"Module":"Generic","Version":"13.2.0.2(sensors)","FallbackTopic":"cmnd/DVES_6D1253_fb/","GroupTopic":"cmnd/tasmotas/"}}
08:44:56.041 RSL: INFO2 = {"Info2":{"WebServerMode":"Admin","Hostname":"tasmota-6D1253-4691","IPAddress":"192.168.0.88"}}
08:44:56.051 RSL: INFO3 = {"Info3":{"RestartReason":"External System","BootCount":8}}
08:44:57.190 QPC: Reset
08:45:00.138 RSL: STATE = {"Time":"2023-12-04T08:45:00","Uptime":"0T00:00:11","UptimeSec":11,"Heap":22,"SleepMode":"Dynamic","Sleep":50,"LoadAvg":19,"MqttCount":0,"Wifi":{"AP":1,"SSId":"Hauis","BSSId":"EC:41:18:EB:E5:09","Channel":3,"Mode":"11n","RSSI":76,"Signal":-62,"LinkCount":1,"Downtime":"0T00:00:05"}}
08:45:00.159 RSL: SENSOR = {"Time":"2023-12-04T08:45:00","EN16X":{"AQIS":2,"eCO2":512,"TVOC":79}}
08:45:22.130 CMD: I2Cscan
08:45:22.150 RSL: RESULT = {"I2CScan":"Device(s) found at 0x38 0x53"}
08:45:28.996 CMD: I2CDriver
08:45:28.003 RSL: RESULT = {"I2CDriver":"7,8,9,10,11,!12,13,14,15,17,18,20,24,29,31,36,41,42,43,44,46,48,69,76,84"}

[sfromis]

You generally cannot add features to the sensors precomposed mix, but instead start from just "tasmota" instead of "tasmota-sensors", and add what you need.

[Haui74]

I tried but same result :(

[HofeBY]

@Haui74

If Console Command "i2cdriver" don´t show driver 43,
so you have to compile your own version of "tasmota.bin" with included driver "AHT20"

Solution for Windows Systems:
Download&install https://code.visualstudio.com/
In VSC add extension SW "PlatformIO IDE"
download&uncompress Binary from https://github.com/arendst/Tasmota
first compile tasmota(ESP8285/ESP8266) and tasmota32(ESP32) will download additional Software & build environment
.
study ...\tasmota\my_user_config.h for possible Drivers & also unwanted Drivers !
.
add wished Driver support in ...\tasmota\user_config_override.h
.
remove unwished Drivers in ...\tasmota\include\tasmota_configurations.h (ESP8285/ESP8266) or tasmota_configurations_ESP32.h (ESP32) mybe Driver by uncomment "#define USE_VEML6070" to "//#define USE_VEML6070"
or disable driver 12 later by command "I2CDriver12 0"
.
Now build "tasmota" or "tasmota32" depending to your CPU
Install ...\build_output\firmware\tasmota.bin or tasmota32.bin to your device
.
done

Maybe try out my german compiled Version https://github.com/HofeBY/Tasmota-Firmware

[Brightness248]

Es geht :)
Von den 36°C nicht erschrecken lassen. Die pcb war gerade gut "durchgewärmt" xD

[Haui74]

Ja ok, mach mal bitte, aber fürn D1 mini. Wenn das dann funzt,werde ich verrückt 😉😂

[Brightness248]

hier der Link: https://github.com/Brightness248/Tasmota_AHT21_binary
Kurze Rückmeldung wäre nett, damit wir das hier schließen können ;)

[Brightness248]

@Haui74

Hat es funktioniert?

[Basti17683]

hier der Link: https://github.com/Brightness248/Tasmota_AHT21_binary Kurze Rückmeldung wäre nett, damit wir das hier schließen können ;)

Ich hab das File in meinem Anwendungsfall auf einem D1 Mini getestet und da funktioniert es leider nicht. Ich beschäftige mich jetzt den ganzen Vormittag mit Visual Studio und PlatformIO aber bekomme den Code nicht kompiliert...

[fairdox]

I am struggling with the same problem. I'm using a SONOFF RE5V1C
I've recompiled tasmota using development 13.3.0.1 and adding #define USE_AHT2x

CMD: i2cdriver
MQT: stat/tasmota_59C993/RESULT = {"I2CDriver":"43"}
CMD: status 4
MQT: stat/tasmota_59C993/STATUS4 . . . "Drivers":"1,2,4,6,7,8,9,10,12,16,18,19,20,21,22,24,26,27,29,30,35,37,45,62,68","Sensors":"1,2,4,5,6,63","I2CDriver":"43"}}
CMD: i2cscan
MQT: stat/tasmota_59C993/RESULT = {"I2CScan":"Device(s) found at 0x38"}

The device 0x38 is found so I2C is working, but there is no telemetry.

I2CDriver returns just driver 43.
but the same driver 43 does not appear in "Drivers"
I don't know the reason

[sfromis]

Well, my point is that the nomenclature AHT2X is "supposed" to be all where the name starts with "AHT2", which only works if there is a strong commonality in how these work. Thus, when claiming that you found a bug, and have a solution, you should make sure that your suggested change is valid for all AHT2X sensors, not just the one you have.

To be clear, not having read the specs, I do not know if using command 0xBE (which you think is "correct") would be OK for AHT25. I'm just pointing out that you need to be extra sure about "corrections" when you only seem to have one of the 3 sensors covered by AHT2X yourself.

[magicman2010]

Your are right, i only checked my AHT20.
I'm wrong, It is not a Bug, Sorry. It is only a solution for the AHT20 sensor type.
I checked the Datasheet for AHT25, this type must be init, with 0xB1 cmd.

[HenryJanssen]

I had the same issue with a combined AHT20 and BMP280 sensor. BMP worked out of the box, AHT20 didn't work. I compared it with the micropython implementation that worked, there the command was indeed 0xBE. I consider this to be a bug. The solution could be to split the generic AHT2X in separate AHT20, AHT21 and AHT25 defines.

[JRzen]

Yep - my AHT20 needed this change as well.

[sichtkunst]

Yes, here the same. With the change to 0xBE my AHT20 works fine in a combination sensor with BMP280.

[vid8266]

magicman2010, judging by the screenshot, do you have a board with ENS160+ATH21? I have the same one and AHT21 didn't work either, replacing the code AHTX_CMD 0xB1 with AHTX_CMD 0xBE helped, both sensors worked!! Thanks for the help, nothing helped!

[magicman2010]

I'm very happy that my solution helped you.
I only tested with an AHT20 sensor.
The AHT21 probably has the same initialization as the AHT20 sensor.

[HenryJanssen]

The change of code would be as I understand the above discussion correct:

#if defined USE_AHT20
  #define AHTX_CMD     0xBE // Cmd for AHT20
  const char ahtTypes[] PROGMEM = "AHT20|AHT20";
#elif defined USE_AHT21
  #define AHTX_CMD     0xBE // Cmd for AHT21
  const char ahtTypes[] PROGMEM = "AHT21|AHT21";
#elif defined USE_AHT25
  #define AHTX_CMD     0xB1 // Cmd for AHT25
  const char ahtTypes[] PROGMEM = "AHT25|AHT25";
#else
  #define AHTX_CMD     0xE1 // Cmd for AHT1x
  const char ahtTypes[] PROGMEM = "AHT1X|AHT1X";
#endif

[HofeBY]

Here is what I ordered:
https://de.aliexpress.com/item/1005006321079856.html?spm=a2g0o.order_list.order_list_main.5.1a5f5c5fVaOEOB&gatewayAdapt=glo2deu

Comiling Tasmota dev 13.4.1.2 with support of
Air quality ENS160 works fine under I2C address 0x53
AHT21 is not working but I2C device is found under 0X38

Connection is done like here, but with az-delivery ESP32 dev Kit
https://www.instructables.com/ENS160-AHT21-Sensor-for-Arduino/

Log:
00:00:00.002 HDW: ESP32-D0WDQ6 v1.0
00:00:00.071 UFS: FlashFS mounted with 288 kB free
00:00:00.093 CFG: Loaded from File, Anzahl 86967
00:00:00.105 QPC: Count 1
00:00:00.108 I2C: Bus1 using GPIO22(SCL) and GPIO21(SDA)
00:00:00.109 SCR: ufilesystem found
00:00:00.173 PCF: Address 0x20 reserved for MCP230xx
00:00:00.240 BRY: Berry initialized, RAM used 3884 bytes
00:00:00.253 Projekt tasmota - 22ESP32 Version 13.4.1.2(tasmota32)-3_0_0(2024.04.20 01:05:08)
00:00:01.314 I2C: EN16X found at 0x53
00:00:03.000 WIF: verbinden mit AP1 SUPERSECRET Channel 1 BSSId EE:67:BC:31:62:57 in Modus HT20 als 22ESP32...
00:00:04.776 WIF: verbunden
17:31:03.010 mDN: initialisiert '22ESP32.local'
17:31:03.020 HTP: Webserver aktiv bei 22ESP32.local mit IP-Adresse 192.168.137.103
17:31:04.055 MQT: Verbindungsversuch…
17:31:04.076 MQT: verbunden
17:31:04.080 MQT: tele/22ESP32/LWT = Online (beibehalten)
17:31:04.081 MQT: cmnd/22ESP32/POWER =
17:31:04.086 MQT: tele/22ESP32/INFO1 = {"Info1":{"Module":"ESP32","Version":"13.4.1.2(tasmota32)","FallbackTopic":"cmnd/22ESP32_fb/","GroupTopic":"cmnd/tasmotas/"}}
17:31:04.099 MQT: tele/22ESP32/INFO2 = {"Info2":{"WebServerMode":"Admin","Hostname":"22ESP32","IPAddress":"192.168.137.103","IP6Global":"","IP6Local":"fe80::cac9:a3ff:fec6:99d4%st1"}}
17:31:04.113 MQT: tele/22ESP32/INFO3 = {"Info3":{"RestartReason":"Software reset CPU","BootCount":361}}
17:31:06.895 QPC: Reset
17:31:08.894 MQT: tele/22ESP32/STATE = {"Time":"2024-04-21T17:31:08","Uptime":"0T00:00:09","UptimeSec":9,"Heap":125,"SleepMode":"Dynamic","Sleep":50,"LoadAvg":19,"MqttCount":1,"Berry":{"HeapUsed":4,"Objects":48},"Wifi":{"AP":1,"SSId":"NW0","BSSId":"EE:67:BC:31:62:57","Channel":1,"Mode":"HT20","RSSI":100,"Signal":-40,"LinkCount":1,"Downtime":"0T00:00:03"}}
17:31:08.920 MQT: tele/22ESP32/SENSOR = {"Time":"2024-04-21T17:31:08","EN16X":{"AQIS":1,"eCO2":404,"TVOC":25},"ESP32":{"Temperature":47.8},"TempUnit":"C"}
17:31:26.059 CMD: I2Cdriver
17:31:26.065 MQT: stat/22ESP32/RESULT = {"I2CDriver":"1,2,7,9,10,22,26,43,44,62,69,81,84"}
17:31:31.173 CMD: I2Cscan
17:31:31.198 MQT: stat/22ESP32/RESULT = {"I2CScan":"Device(s) found on bus1 at 0x38 0x53"}

Does anyone have such a module working with AHT21?
What can I do to get it functional ?

[magicman2010]

Das !12 sagt der Treiber ist deaktiviert. Und die anderen Treiber sind aktiv, sofern ein passender Sensor am I2C Bus angeschlossen ist.

Guck mal das, evtl musst du hier noch was anpassen:
#20163 (reply in thread)

[Basti17683]

Ok danke dir! Dann hätten wir jetzt wohl das Übel gefunden. Darf ich fragen ob mir das jemand anpassen kann oder mir nen crashkurs in Visual Studio und Platformio gibt? Ich stell mich da echt zu doof an 🫣 hab da gestern 6h weggeschossen und war kein Stück weiter.

[HofeBY2]

@Basti17683
OK, Treiber 12 ist nun geblockt, aber es wird kein Treiber bei "I2Cdriver" angezeigt & somit ist diese Tasmota Ausgabe OHNE Treiber
AHT2x (Index Nr.43) compiliert.
Ein AHT2x Sensor wird hier nicht funktionieren !
Du brauchst eine Version in der der AHT2x Treiber enthalten ist.

[magicman2010]

Hab mir gerade mal das Datenblatt angesehen, für den AHT21 muss 0x71 als Initialisierung gesendet werden.
Du musst dir mal den Treiber im Tasmota ansehen.
Das wäre der Ablauf gemäß AHT21 Datenblatt:

7.4 Sensor Reading Process

1. After power-on, wait for ≥100ms. Before reading the temperature and humidity value, get a byte of status word
   by sending 0x71. If the status word and 0x18 are not equal to 0x18, initialize the 0x1B, 0x1C, 0x1E registers,
   details Please refer to our official website routine for the initialization process; if they are equal, proceed to the next
   step.
2. Wait 10ms to send the 0xAC command (trigger measurement). This command parameter has two bytes, the first
   byte is 0x33, and the second byte is 0x00.
3. Wait 80ms for the measurement to be completed, if the read status word Bit[7] is 0, it means the measurement
   is completed, and then six bytes can be read continuously; otherwise, continue to wait.
4. After receiving six bytes, the next byte is CRC check data, which the user can read as needed. If the receiver
   needs CRC check, it will send an ACK reply after receiving the sixth byte, otherwise it will send a NACK reply. The
   initial value of CRC is 0xFF, and the CRC8 check polynomial is:
   CRC [7:0] = 1+X4+X5+X8
5. Calculate the temperature and humidity value
   Note: The calibration status check in the first step only needs to be checked when the power is turned on.No
   operation is required during the acquisition process.

Ich denke mal wie obern beschrieben anstatt 0xBE 0x71 an den Sensor senden.

[HofeBY2]

@Basti17683
Man kann mit Dir z.Z. nicht per Github Mail Kontakt aufnehmen, das müsstetst Du zuerst freischalten.

Man könnnte sich via https://rustdesk.com/de/ auf Deinen Rechner aufschalten & die Entwicklungsumgebung einrichten.
Selber Compilieren ist bei weitem nicht so einfach ! Ich halte eine Unterstützung für essentiell.

Aber Du solltest zuerst einmal eine Tasmota.bin (auch ältere) mit AHT2x Support installieren.

Ich würde Dich via https://rustdesk.com/de/ unterstützen.

[Lassska]

Hi,
For ENS160+ATH2x

#ifdef USE_AHT1x
#undef USE_AHT1x
#endif
#ifndef USE_AHT2x
#define USE_AHT2x
#endif
#ifndef USE_ENS16x
#define USE_ENS16x
#endif

#endif // USER_CONFIG_OVERRIDE_H

stat/Bedroom/RESULT = {"I2CDriver":"!7,!8,9,10,11,!12,13,14,15,17,18,20,24,29,31,36,41,42,43,44,46,48,69,76,84,89"}

AHT2X requires calibration because it seems that the ENS160 "gas" sensor heats up and dries out...
In my case tempoffset -4 , humoffset 10

[sfromis]

I'd keep any of those "fake CO2" sensors at a good distance from temperature sensors, instead of the bad combo of having them on the same small module. While your not-really-calibration may appear to help, you cannot assume that the offset is constant across ranges of temperature and humidity.

"Real calibration" is much more complex than applying a single offset.

[Lassska]

I didn't even think of using the temperature read from this sensor, but in the house it is relatively constant, so for the "fake" sensor, I think it was still better to receive the correct temperature to display something a little comparable, but I assume that even if the sensors collaborate with each other (ENS160 address 0x13 TEMP_IN) this calibration only has an effect in the tasmota... Thank you very much, you helped me to judge them better!