AC adaptor interfering with ESP8266 - WS2812b led strip

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Hi, i have 2 power adaptors connected on same AC line, both grounded.

Power adaptor 1. 12V DC 10A for powering 12v led strips, controlled by ESP8266, IRLZ44N MOSFET used to control brightness of the led strips. This works fine without any issue.

Power adaptor 2. 5v DC 5A for powering 5v WS2812b led strip, controlled by ESP8266. This is giving problems.There is random flicker on all led lights.

The led strip is at a distance of 5 feet from ESP8266.

  • Tried using a single led pixel soon after the controller, but that didn't help.
  • Tried using 100uf caps between power close to led strip.
  • Tried using 100uf cap on ESP power
  • Tried using 220ohm resistor in series on data line close to led strip

I am now using SP901E signal booster, but the issue persists.

Few observations:

  • AC Power adaptor 1 gives a whining noise when the LED brightness is reduced, If a turn off this adaptor, or set brightness to 0, the flicker is gone instantly. Tried replacing with another adaptor, same results.
  • If I measure for frequency(using multimeter) between VCC and DIN on WS2812B strip, the flicker is gone too(power adaptor 1 still powered on)

The voltage is around 5.5v on the led strip, which i think is not an issue here, as the flicker goes away in the above 2 scenarios.

How and why is the other AC adaptor generating noise on the esp controller which is connected to a different power source ?

How does measuring for frequency on a multimeter on solve the flicker issue.(getting frequency - 113-120 KHZ)

Thanks :slight_smile:

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The ESP is a 3.3V device. (You show 5V but I'm pretty sure the chip itself is running on 3.3V.)

The LED strips want a 5V data signal and you are probably on the "hairy edge". Adafruit has lots of information (and some solutions).

I would expect that to help but it may "want" a 5V signal too. I couldn't find any detailed specs and it's not clear that it's made to solve this particular problem.

That can contribute to the problem. If you can't adjust-down the voltage try putting a diode in series with the power to the LED strip. That will drop about 0.7V. Make sure the diode is rated to handle the current. Estimate 60mA per LED "worst case" with all LEDs at full-brightness white.

You probably replaced with the same model power adapter. It's probably just a "characteristic" of that particular power supply and not necessarily a "defect" and not the root-cause of your problems.

You could try "replacing" the meter with a resistor... 100K shouldn't hurt anything. But if that works it's just a "hack" and not really a proper solution.

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