Tasmota with only BME280 - compile config into firmware

[francwalter]

Hello
I need a Tasmota with only the BME280 sensor.
Is it enough if I include into my user_config_override.h the following definitions?

...
#define USE_I2C
#define USE_BME280
...

instead of using in platformio.ini

default_envs = tasmota-sensors

which is the whole sensors pre-built, but only:

default_envs            =  tasmota-mysensor
...
[env:tasmota-mysensor]
board                   = esp8266_4M2M
build_flags             = ${env:tasmota.build_flags}

And how can I compile my GPIO configuration into the firmware?
I need to config

GPIO4 (D2) → I2C SDA
GPIO5 (D1) → I2C SCL

It took me a while (and several useless compilations) to understand, that if I change to
Configuration > Module > Module Type: Generic (18)
I have to reboot, until all the GPIO and I2C entries are visible and not only some 5 or so.

But I dont want to edit the Configuration manually (I need 42 ESPs with the same firmware), I want to have it already in my firmware. But how?

Thanks.frank

[francwalter]

In Compiling Doc I just found in USER_BACKLOG section the example:
#define USER_BACKLOG "WebGetConfig http://myserver/tasmota/conf/%id%.dmp"
which could be exactly what I need. I could do e.g.:
#define USER_BACKLOG "WebGetConfig http://192.168.0.90/tasmota/conf/%id%.dmp"
And also Templates.

[sfromis]

To have gpios configured at build time, create a template in the web UI, and set it using the symbol USER_TEMPLATE. Default-enabled with #define MODULE USER_MODULE. This is what I'd recommend instead of any use of WebGetConfig in USER_BACKLOG (unless you have more complex updates).

Again and again, forget all that crap you got from Grok (or whatever guessing method). There exists no USE_BME280 symbol, this is merely a hallucination. The driver can be included with USE_BMP instead.

To have a build including the 4M board setup for a file system, the simplest is to build tasmota-4M after having done all of your other defaults updates (including #define USE_BMP) in user_config_override.h, meaning that this is the only file you need to modify before building.

Note that with a 4M build, you do not need to have tasmota-minimal.bin.gz on your local OTA server, as 4M allows the OTA upgrades to happen without the "minimal" step.

If you do not actually need the extra features with a 4M build (like the file system), you could also build tasmota-sensors, with your other build amendments (excluding USE_BMP) in user_config_override.h. Note that you cannot OTA update between 4M and not, if the wired flashing was not done with a 4M build in the first place.

[francwalter]

Note that with a 4M build, you do not need to have tasmota-minimal.bin.gz on your local OTA server, as 4M allows the OTA upgrades to happen without the "minimal" step.

Only now I understand this!
I had not uncommented the: board = esp8266_4M2M in [env] and now, when I just tested my Group Update with two ESPs they showed this:

So there I would need manual interaction, thats not what I want.
I thought the Update is fully automatic even with the tasmota-minimal.bin.gz
I will flash now with the:
board = esp8266_4M2M in [env]

[sfromis]

No problem there, no need for manual interaction, just refresh the page. After that, the red warning goes way. Since it shows sensor values (which the minimal build cannot), it did successfully upgrade.

It will be fine to use a non-4M build, you'll just have to decide which way, as you cannot first flash a 1M build and then upgrade to a 4M build, while the other way works too.

[francwalter]

OK then, I'll go for the tasmota-sensors.bin which already worked with my sensor.
I thought that this firmware has many other sensors I dont need and I could save some space like this.
So my plan is:

1. Flash the tasmota-sensors.bin (with my own settings in the config) by just uncommenting the tasmota-sensors in platformio.ini (EDIT: Sorry, I ment: platformio.override.ini)
2. Set up the Configuration with my two GPIOs 4 and 5 so my sensor is actually working and displays the values
3. Run the Template command in ESP's Console and copy the value
4. Define MODULE USER_MODULE and USER_TEMPLATE (with my Template's content) in my config
5. Compile, erase and flash the new firmware, leaving the tasmota-sensors-minimal.bin.gz on my Update Server.

[sfromis]

You do not need to modify platformio.ini at all, you can just select the relevant build environment when starting the build, instead of modifying the default first. And do not rename the copied tasmota-minimal.bin.gz first, Tasmota will automatically modify the name.

Indeed, tasmota-sensors does include a lot of other sensors, but "saving space" is only useful if you want to use the space for something else instead.

[francwalter]

And do not rename the copied tasmota-minimal.bin.gz first, Tasmota will automatically modify the name.

This I dont understand. Do I just put the original (downloaded) tasmota-minimal.bin.gzinto my OTA directory? I think I read somewhere, that it has to be named like the main firmware just with -minimal after the name part?
But maybe this is again some tale from AI and I mix it up 😏

I want to keep my firmware so slim as possible, especially for update reasons. But if the sensors firmware with all sensors is just e.g. 10 kB bigger at size, it is not relevant.
I could try to #undef all the other sensors and try and error to compile and flash but this promises me again some days of successless walking in the dark, I fear.

[sfromis]

That part about renaming was what I already told you was not really recommended. If what you suggested was required, the standard tasmota-sensors.bin.gz would also need a tasmota-sensors-minimal.bin.gz which is not the case. The logic is that it keeps the part before the first dash, and then modifies. As all recommended binaries for ESP8266 has a name starting with tasmota- (or just tasmota.), the name is then tasmota-minimal.bin.gz.

Saying "for update reasons" is no reason at all, without mentioning what benefit you hope for. Yes, the sensors binary is larger, but that does not cause problems in the normal upgrade flow, especially if you have first flashed a 4M build, meaning that you no longer even need a minimal at all, to be able to upgrade. Arguably, using a 4M build (instead of sensors) would give the simplicity of this also being the first binary flashed via wires, meaning that this allows further upgrades without minimal, and without needing to remember this with next device(s) you add.

Sure, you could construct a reduced custom build, eliding sensors and other features, if you have a good case for getting a real benefit from it. If you don't care about benefits, you deserve to have fun learning the ropes yourself 😀

[francwalter]

OK then, it works with this in my platformio_override.ini:

...
default_envs = tasmota-sensors
...

and this in my user_config_override.h:

...
#define MODULE USER_MODULE
#define USER_TEMPLATE "{\"NAME\":\"BMP280\",\"ARCH\":\"ESP8266\",\"GPIO\":[0,0,0,0,640,608,0,0,0,0,0,0,0,0],\"FLAG\":0,\"BASE\":18}"
...

Next thing is the TelePeriod, I need 30 seconds, default is 300 but I need an MQTT value every 30 seconds.
AI proposed me this:

#undef  USER_BACKLOG
#define USER_BACKLOG "TelePeriod 30"

But I am very sceptical, if this is not some hoax again. How is it really done?

EDIT: INCREDIBLE! The AI was right! That works 👍