Pwm dimmer correction

ESPHome
1

Hello,
I have an esp8266 dimmer configured like this

esp8266:
  board: esp01_1m
  restore_from_flash: true

output:
  - platform: esp8266_pwm
    pin:
      number: GPIO14
      inverted: yes
    frequency: 1000 Hz
    id: pwm_output

# Example usage in a light
light:
  - platform: monochromatic
    output: pwm_output
    name: ${switch_name}
    restore_mode: ALWAYS_ON

this is working well, but there is only light for percentages 34 and higher,
in some occasions I have light on 32%, probably this has to to with software pwm.

but I want a correction so the first bit of light will be there when I select 1%.
is this possible?
this because of the smooth affect if just takes too long before any light shows up when turning on.
I might can do something about the effect, but I actually like it.

2

Ya, the software pwm isnt as good but, its not bad either. You can try playing around with lower frequencies and see if you can find a happy medium. I use esp8266 to run monochromatic lights all over my house and i can tell you now, dont gold your breath for a smooth transition from 1-100% its not happening. Mine dont start turning on untill 8% and thats reasonable for me. One of the most overlooked parts of the equation are the lights themselves. Some cheaper lights just dont do dimming well.

Im curious why you are inverting your pwm output. Did you make the dimming circuit with a mosfet?

What is your hardware?

3

I know the issue is because of my cheap bulb, that was why I was hoping for a software correction :wink:

I am using this bulb

the tasmota configuration said pwm_i so I took that as inverted and it’s working.

for Tasmota btw I had the same issue, the light not being on on low percentages, but it didn’t have this smooth transition so there I didn’t notice.

when I get home I will try lowering the frequency and see what it does. the current value is copied from the example in the documentation.

5

Hhmm… the technical documentation describes it as “capable of stepless dimming”. I was really looking for information that would explain the inverted output. Its going to bug me not knowing… when you play around with the frequency settings, would you mind seeing what happens if you dont invert the gpio? Worst case scenario it just wont work and just add the invert back fix it.

Ive never heard of this brand of bulbs and there are so few capable of changing the firmware, its nice to know of another one. Do they come preflashed with tasmota? Is it difficult to change it to esphome?

6

I checked some stuff,
If I remove inverted: yes it inverts,
0% is fully on, and 100% is fully off, the strange thing is that at 97% there is already a bit of light, where not inverted the correction was 35%, not only 2.

No, they come with tuya.
Mine is couple of yours old and I could use tuya-convert to migrate to tasmota.
but check the warning at the bottom of the device page, tuya has changed trom esp to bk72xx.
Tasmota esp8266 just accepts esphome files for firmware update.(you might need to use tasmota minimal first because else the file is to big)
I think if you get a new model you should use cloudcutter to migrate to esphome.

but you can actually use that for almost all tuya lights, I have a couple came over from Abroad, just hoping there to be an esp chip, but no luck, then I found cloudcutter and I could use those devices. But I can also buy them in the local store.

changing the frequency didn’t make any difference for me. So I just decided to remove the transition time.

esp8266:
  board: esp01_1m
  restore_from_flash: true
  early_pin_init: false

output:
  - platform: esp8266_pwm
    pin:
      number: GPIO14
      inverted: yes
    # frequency: 1000 Hz
    id: pwm_output

# Example usage in a light
light:
  - platform: monochromatic
    output: pwm_output
    name: ${switch_name}
    restore_mode: ALWAYS_ON 
    default_transition_length: 0s

no thers is no transition, there wasn’t any for Tasmota anyway and the behaviar is the same.