The Smart Light that will not turn off

The Smart Light that will not turn off

A little while ago I had a blackout and lost power to everything running, including all my smart devices. Eventually power came back up and everything was functioning as normal, however I noticed that the kitchen LED strip was glowing blue. This was alittle strange as I knew it was off. But to check I powered it off and back on again, and it glowed blue again.

Thinking that there had been something wrong I went searching the internet to try to understand what was happening and how I might fix it.

As it turns out it is actually a more common problem then I had thought and it can effect any type of light that uses LEDs.

What is actually happening is a small amount of voltage is being recieved by inductng power from nearby sources. The LED and/or its cabling is in a position or shape where they can act as an inductor of power.

The LED driver would still be pulling constant power for the wifi signal on the chip and that induced power is lighting the LED just enough to register it being dimly lit.

This is a great video explaining the concept.

How to fix

It really depends on the type of scenario. Below are a couple of ways that have worked for me but sometimes it can be experimenting to see what works best for you.

Solution 1: Reflash ESPHome configuration File

So when I initially saw this problem, one of the things I tried was going between the two different light functions in ESPHome, monochromatic and rgbw. I originally though that I had programmed it wrong. So I switched between the two modes only to realise that I had actually got it right the first time round.

What I found during the process of changing between these modes activated something in the circuitry which cuts the power and prevents this from happening. The downsides are that if the power is lost, I have to perform this process again and I have to flash two different versions of the configuration each time. Lukily we don't get two many blackouts.

So what I setup in the ESPHome configuration file is:

Config1:

light:
  - platform: monochromatic
    name: "Kitchen Undercupboard LED Lights"
    id: white
    output: white_channel
    restore_mode: ALWAYS_OFF
    default_transition_length: 0.25s

output:
  - platform: esp8266_pwm
    pin:
      number: GPIO5
    id: white_channel
    inverted: False
    ```

When loss of power occurs, comment out Config1 and enable Config2.

Config2:

light:
  - platform: rgbw
    name: "Kitchen Undercupboard LED Lights"
    red: output_red
    green: output_green
    blue: output_blue
    white: output_white
    restore_mode: RESTORE_DEFAULT_OFF

output:
  - platform: esp8266_pwm
    id: output_red
    pin: GPIO4
  - platform: esp8266_pwm
    id: output_green
    pin: GPIO12
  - platform: esp8266_pwm
    id: output_blue
    pin: GPIO14
  - platform: esp8266_pwm
    id: output_white
    pin: GPIO5

Perform OTA flash with Config2 setup. Once flashed comment out Config2 and uncomment Config1. Perform OTA flash again.

For me this fixes the issue, but this may not fix it for you.

Solution 2: Check sheilding and wiring

This may not be possible for all things, but in the case of LED strips that have been cut in half, make sure that you have properly sheilded the RGBW channels. I believe in my scenario this could be why I am seeing the issue.

Maybe the problem?

Solution 3: Move the switch/ relay closer to the device

This obviously is not the answer to everything, but in some cases positioning the relay or switch closer may be enough to help. Again, its very much a trial an error type task but having a bit of an understanding to why it might be happening is useful.