[question] How to handle unusual device values with home assistant discovery.

[joshkay]

I'm trying to implement a control for my innovelli led bar. The switch is expecting the brightness value to be one of 0%, 10%, 20% etc. I cannot see a way to accomplish this using the default MQTT light schema.

Instead, I have managed to implement it using the template MQTT light schema. I have this working using the template schema, but I cannot implement the RGB portion using that schema because it doesn't support RGB commands on a separate topic.

I have setup the custom device in customDevices.json. Below is the config:

{
    "798-1-1": [
        {
            "type": "light",
            "object_id": "led",
            "values": ["112-1-13", "112-1-14"],
            "discovery_payload": {
                "schema": "template",
                "command_topic": "112-1-14",
                "command_on_template": "{{ (brightness / 255 * 10) | round(0) if brightness is defined else 5 }}{{0}}{{'%'}}",
                "command_off_template": "0%",
                "state_topic": "112-1-14",
                "state_template": "{{ 'off' if value_json.value == '0%' else 'on' }}",
                "brightness_template": "{{ value_json.value | regex_replace(find='%', replace='', ignorecase=False) | round(0) / 100 * 255 }}"
            }
        }
    ]
}

I'm wondering if there's a way to handle converting the brightness & rgb values on the zwave2mqtt side of things so it can accept a standard request from home assistant.

[robertsLando]

@joshkay Have you tried to ask home assistant for a feature request? I mean, adding rgb commands on a separete topic?

[joshkay]

I brought it up on Discord and they told me to use their implementation of OZW. So I thought I'd see what your opinion was before pressing the issue with them. Thoughts?

[robertsLando]

How do you expect me to send that value? What's the format you need?

[joshkay]

I was looking for a way to process the incoming/outgoing mqtt messages before sending the zwave command.

For example, if a brightness set command is sent and the value is 0-10, i would need to convert that to a string and add a % sign to the end of it before sending that command to the zwave device for it to respond properly.
Same thing with getting the value of the brightness, but in reverse. Remove the % sign and send the number alone.

Dealing with the RGB values is a lot more complex, because the device just represents it as a single number from 0-255. It looks like it represents the hue range.

Maybe there could be a way to have custom js function that could convert the values?

Just throwing out ideas.

[robertsLando]

Maybe there could be a way to have custom js function that could convert the values?

That could be the way. I could add a field to convert the value when publishing and one to convert the value when reading, what about this?

[robertsLando]

@joshkay I have implemented this. Will merge soon :)

[joshkay]

@robertsLando Wow that's amazing! Thanks

[joshkay]

Would it be possible to store this to the devices file? This way if other people are looking to implement an Inovelli Red Switch in the future with home assistant it would just work for them without needing to add these functions to the gateway values table?

This implementation should work just fine for me, but I'm wondering if there's a better way for this to work out of the box for new users (for these strange devices).

[robertsLando]

It would be difficult to add that to a device template, for a design reason, because when a value it's published to mqtt, the gateway publish it without knowing if there is a discovered device/value associated

[joshkay]

Okay no problem. Just food for thought.