Toggling an LED between two values (50% & 100%)

ESPHome
1

Working my way through a a program to drive a LOLIN 2.4" Display (ILI9341 & XPT2046) step by step, I have got this far:

output:
  - platform: ledc
    pin: GPIO22 #Silkscreen D1 jumpered to TFT-LED (backlight)
    id: backlight
  
light:
  - platform: monochromatic
    output: backlight
    id: backlightctl
    name: backlightctl
    restore_mode: ALWAYS_ON

touchscreen:
  platform: xpt2046
  id: my_touchscreen
  cs_pin: GPIO17 #touch T_CS
  update_interval: 50ms
  threshold: 400
  on_touch:
    - if:
        condition:
          - light.is_on:
              id: backlightctl
        then:
          - light.dim_relative: 
              id: backlightctl
              relative_brightness: -50%
        else:
          - light.turn_on:
              id: backlightctl

With the above my display will switches between three states: 100%, 50% & OFF.
How can I test the current state of backlightctl so that I can toggle between 100% and 50%?

Regards, Martin

2
1 Like
3

You need an if-then-else

If - brightness is 100%

then - brightness 50%

else

if - brightness 50%

then - brightness 100%

Its much easier if you just think about what you want to happen step by step.

Your also using “relative brightness” which if you read the documentation dims a light by the % you set so, at 50% if you press it again it will keep going down by -50%.

How do you get from 50% to 100%? Not by setting relative brightness-50%.

Also, it looks like your setting this up wrong. Anytime you touch the screen then it will toggle tour brightness. That doesnt make a “touch” screen very useful if it bounces between 100% and 50% each time you use it.

4

Seeing as were in 2024, a lot has changed since April of 2021 and those old posts arent all that helpful for thing, especially simple things like changing brightness.

5

Unless I need to change my glasses, OP is asking how to read brightness from an ESPHome light.

I’m pretty sure that didn’t change since 2021.

6

Thank you all for your advice. For the benefit of any esphomer’ers that are looking for clues to address this problem, this was my solution:

output:
  - platform: ledc
    pin: GPIO22 #Silkscreen D1 jumpered to TFT-LED (backlight)
    id: backlight
 

light:
  - platform: monochromatic
    output: backlight
    id: backlightctl
    name: backlightctl
    restore_mode: ALWAYS_ON

touchscreen:
  platform: xpt2046
  id: my_touchscreen
  cs_pin: GPIO17 #touch T_CS
  update_interval: 50ms
  threshold: 400
  on_touch:
    - if:
        condition:
          - lambda: 'return id(backlightctl).current_values.get_brightness() == 0.5;'
        then:
          - light.dim_relative: 
              id: backlightctl
              relative_brightness: +50%
        else:
          - light.dim_relative: 
              id: backlightctl
              relative_brightness: -50%

Regards, M.

1 Like