Error: Requesting data from DHT failed! (I need some help)

[ServiceXp (RJ)]

I’m at a loss here. I have 4 DHT’s connected to an ESP32 that use to work for ~8 months.

At some point about a month ago, I started fighting with the error below. After a power up, it will work for several hours and then one or more and then eventual all the attached sensors end up in this state. A full 5 min power cycle is required to bring them back on-line.

Tried:
All new sensors
New ESP32 Board
New 2.5a Power supply and wire.
New higher tolerances pull up resistors, in different values (2K to 4.7)

Error

[17:52:56][W][dht:169]: Requesting data from DHT failed!
[17:52:56][W][dht:060]: Invalid readings! Please check your wiring (pull-up resistor, pin number).

Sketch

esphome:
  name: "erv-monitor-sensors"
esp32:
  board: esp32dev
  framework:
    type: arduino

# Enable logging
logger:

# Enable Home Assistant API
api:
  encryption:
    key: "XXXXXXX"
ota:
  password: "XXXXX"
wifi:
  ssid: !secret wifi_ssid
  password: !secret wifi_password
  fast_connect: true
  power_save_mode: none
  
# Enable fallback hotspot (captive portal) in case wifi connection fails
  ap:
    ssid: "erv-monitor-sensors"
    password: "XXXXX"

captive_portal:
sensor:
  - platform: dht
    model: DHT22
    pin: 19
    temperature:
      name: "Stale Air Port Temperature"
    humidity:
      name: "Stale Air Port Humidity"
    update_interval: 10s
  - platform: dht
    model: DHT22
    pin: 23
    temperature:
      name: "Exhaust Air Port Temperature"
    humidity:
      name: "Exhaust Air Port Humidity"
    update_interval: 15s  
  - platform: dht
    model: DHT22
    pin: 5
    temperature:
      filters:
        - offset: 0
      name: "Outside Air Port Temperature"
    humidity:
      filters:
        - offset: 0
      name: "Outside Air Port Humidity"    
    update_interval: 20s
  - platform: dht
    model: DHT22
    pin: 18
    temperature:
      name: "Fresh Air Port Temperature"
    humidity:
      name: "Fresh Air Port Humidity"
    update_interval: 25s

[ServiceXp (RJ)]

So I think I’ve found the cause, but have no ideal what to do to correct it.

It appears the ERV itself is causing power line interference that is causing the DHT’s to go off line. Happens when either turning on or off the ERV. The ESP32 runs fine when unit doesn’t turn off.

There is only one power source in my attic, and it’s the same that powers the ERV and the ESP32.

So I ran an extension cord to another receptacle (different circuit) in the house into the attic to power the ESP32. When the ESP32 is running on a different circuit it runs perfectly without issues.

I’ve tried using an isolated power transformer, both powering the ESP32 OR the ERV and the ‘noise’ still breaks through and causes the problem.

I’ve tried a good 2.5a 5vdc power supply with Ferrite bead and the ‘noise’ still breaks through and causes the problem.

Anyway to really filter the ESP32’ power source?

[ServiceXp (RJ)]

After trying many, many power combinations, this (for whatever reason) works in it’s exact combination.