Using a sensor value to control the brightness of a light in HA

ESPHome
1

Hello!

I would like to build a sort of wifi remote control with an Esp32 (and espHome).
I am using a potentiometer with adc on the esp, I get the value in HA as a sensor, this works fine.
But I want to use the value of the pot to control for exemple the brightness of a light that is connected to HA like a PhilipsHue bulb, or the color (RGB if I have 3 pot for exemple), or the speed of an fastLed effect (adressable led strip).

Is that possible? Can I do that in an automation or a script? If that is possible could someone tell me how to proceed?

Thank you :wink:

2

See this post which has most of what you need.

You will need an automation to call the turn_on service, just template the brightness using the value of your sensor, making sure it falls in the range of 1-255.

Edit: You can use a single turn_on automation to control your light to be on or off. Just trigger the automation with a change in sensor value, and make it be in the range 0-255. A brightness of zero turns the light off (even though you are calling light.turn_on).

3

Thank you very much! I’ll try. :wink:

4

Hello,
I tried this sketch in a script but I get an error.

“light.cuisine” is the light I want to control and “sensor.potentiometre” is my pot value.

Sketch:


alias: potentiometre to control brightness

service: light.turn_on
target:
  entity_id: light.cuisine
data:
  brightness: '{{ states(''sensor.potentiometre'') }}'

Error:


Key malformed: invalid slug L (try l)

It’s my first time playing with variables in HA so I’m a noobie :slight_smile: :sweat_smile:

Thanks for help :wink:

5

I think you have got it confused with your quotes.

Try like this:

alias: potentiometre to control brightness

service: light.turn_on
target:
  entity_id: light.cuisine
data:
  brightness: "{{ states('sensor.potentiometre') }}"

You have used two single quotation marks instead of the double quote mark.

6

Also you can test your templates in Developer Tools (the little hammer on the toolbar, then under the Template tab). If you paste "{{ states('sensor.potentiometre') }}" into there it should display the value of the sensor.

7

Yes I got a bit confused I don’t really know what i’m doing with this sketch :sweat_smile:
I’ve tried with your sketch and I got this error:


Message malformed: expected float for dictionary value @ data['brightness_pct]

By the way I’ve used “brightness_pct” because my value goes between 0 and 100

I think that my value is not the good variable type.

How can I fix this?

Thank you very much

8

If you paste just the template in the template editor, what is returned?

Assuming it’s fine, try removing the double quotes around the templated value.

Also - if you use from 0-100 as your value, your light will never get to full brightness.

9

I’ve put it in the template editor and it worked, the value of the pot is displayed! Already a victory for me! :sweat_smile:

But I still get the same error as before:


Message malformed: expected float for dictionary value @ data['brightness_pct]

I think I have to convert the variable type form string to float. But I don’t know how to do that.

Thank you very much! :slight_smile:

10

Did you get this working? If not post the whole automation for controlling the light, not just snippets.

11

No I didn’t. I still get errors.

Here is my script:


alias: Brightness using pot
sequence:
  - type: turn_on
    device_id: 91bf21e23839e3659d64534b63611eec
    entity_id: light.cuisine
    domain: light
    brightness_pct: {{ states('sensor.potentiometre') }}
mode: single

And here is the error I get


Message malformed: expected float for dictionary value @ data['brightness_pct]
12

Ah - a script - ok - this is tested and works:

light_adjust_with_pot:
    alias: Brightness using pot
    sequence:
      - variables:
          new_brightness: "{{ states('sensor.potentiometre') | float }}"
      - service: light.turn_on
        data: 
          device_id: 91bf21e23839e3659d64534b63611eec
          entity_id: light.cuisine
          domain: light
        data_template:
          brightness_pct: "{{ new_brightness }}"
    mode: single
13

It works! Thank you so much!

I like this forum. Everybody try to help and I think this is beautiful.

If I was living near of you I would pay you a drink.

Thanks again for help :wink: