Controlling Noctua PWM fan with ESP8266

ErikNL · April 20, 2023, 10:58am

I have a noctua NF-A20 fan that I would like to control with a D1 mini and ESPHome. Using this topic as a reference: PWM Fan Controller

I created this configuration:

esphome:
  name: pwm-fan-controller
  friendly_name: pwm fan controller

esp8266:
  board: d1_mini

# Enable logging
logger:

# Enable Home Assistant API
api:

ota:
  password:

wifi:
  ssid: !secret wifi_ssid
  password: !secret wifi_password

  # Enable fallback hotspot (captive portal) in case wifi connection fails
  ap:
    ssid: "Pwm-Fan-Controller"
    password: 

captive_portal:
    

sensor:
  - platform: pulse_counter
    pin:
      number: D2
    name: Fan Speed
    id: fan_pulse
    unit_of_measurement: 'RPM'
    filters:
      - multiply: 0.5
    count_mode:
      rising_edge: INCREMENT
      falling_edge: DISABLE
    update_interval: 5s

output:                                                                                                                                                                         
  - platform: esp8266_pwm
    id: fan_speed
    pin: D1
                                                                                                                                                                  
    frequency: "25000 Hz"
                                                                                                                                                                  
    min_power: 13%
    max_power: 100%

fan:
  - platform: speed
    output: fan_speed
    name: fan speed
    id: fan_toggle

Controlling the fan seems to work, when I move the slider up, the fan increases it’s speed, when I move it down, it decreases it’s speed. I am however facing 2 issues:

The reported RPM is incorrect, the fan has a minimum rpm of 350 and a max of 800, I get RPM values between 1500 and 3392. According to the documentation (https://noctua.at/pub/media/wysiwyg/Noctua_PWM_specifications_white_paper.pdf) the current code should be ok:

All Noctua fans provide a tachometer output signal of the following characteristics:
• two cycles per revolution

When I have a look at the log when the fan is running at full speed, I see that the pulse counter is all over te place:

[D][pulse_counter:174]: 'Fan Speed': Retrieved counter: 3348.00 pulses/min
[D][sensor:126]: 'Fan Speed': Sending state 1674.00000 RPM with 2 decimals of accuracy
[D][pulse_counter:174]: 'Fan Speed': Retrieved counter: 3779.24 pulses/min
[D][sensor:126]: 'Fan Speed': Sending state 1889.62207 RPM with 2 decimals of accuracy
[D][pulse_counter:174]: 'Fan Speed': Retrieved counter: 4132.13 pulses/min
[D][sensor:126]: 'Fan Speed': Sending state 2066.06616 RPM with 2 decimals of accuracy
[D][pulse_counter:174]: 'Fan Speed': Retrieved counter: 3894.55 pulses/min
[D][sensor:126]: 'Fan Speed': Sending state 1947.27380 RPM with 2 decimals of accuracy
[D][pulse_counter:174]: 'Fan Speed': Retrieved counter: 3649.46 pulses/min
[D][sensor:126]: 'Fan Speed': Sending state 1824.72986 RPM with 2 decimals of accuracy
[D][pulse_counter:174]: 'Fan Speed': Retrieved counter: 4120.12 pulses/min
[D][sensor:126]: 'Fan Speed': Sending state 2060.06006 RPM with 2 decimals of accuracy
[D][pulse_counter:174]: 'Fan Speed': Retrieved counter: 3888.00 pulses/min
[D][sensor:126]: 'Fan Speed': Sending state 1944.00000 RPM with 2 decimals of accuracy
[D][pulse_counter:174]: 'Fan Speed': Retrieved counter: 4700.24 pulses/min
[D][sensor:126]: 'Fan Speed': Sending state 2350.11987 RPM with 2 decimals of accuracy
[D][pulse_counter:174]: 'Fan Speed': Retrieved counter: 5704.56 pulses/min
[D][sensor:126]: 'Fan Speed': Sending state 2852.28174 RPM with 2 decimals of accuracy
[D][pulse_counter:174]: 'Fan Speed': Retrieved counter: 12396.00 pulses/min
[D][sensor:126]: 'Fan Speed': Sending state 6198.00000 RPM with 2 decimals of accuracy
[D][pulse_counter:174]: 'Fan Speed': Retrieved counter: 11397.72 pulses/min
[D][sensor:126]: 'Fan Speed': Sending state 5698.86035 RPM with 2 decimals of accuracy
[D][pulse_counter:174]: 'Fan Speed': Retrieved counter: 11978.40 pulses/min
[D][sensor:126]: 'Fan Speed': Sending state 5989.19775 RPM with 2 decimals of accuracy
[D][pulse_counter:174]: 'Fan Speed': Retrieved counter: 11604.00 pulses/min
[D][sensor:126]: 'Fan Speed': Sending state 5802.00000 RPM with 2 decimals of accuracy

The other issue I have is that when I set the fan to off / 0, it still keeps spinning. Any idea what the issue could be? I tried playing around with the “min_power”, but that doesn’t seem to help.

I have the fan connected to a 12v power supply, while the D1 mini gets it’s power via USB. I have the GND’s of the 2 power sources wired to eachother.

ErikNL · May 8, 2023, 10:23am

I think I’ve figured it out. The rpm’s where not right, because I did not add the resistor between the rpm pin and the 12v line, like in the schematic in PWM Fan Controller.

The problem with not being able to stop the fan completely seems to be that these Noctua fan’s don’t support anything below 20%, I fount this in a datasheet:

Operation below 20% PWM duty-cycle is not officially supported in the Intel specification
(undefined behaviour). However, most Noctua PWM fans can be operated at below 20%
and will stop at 0% duty-cycle. Only the following models keep running at their specified
minimum speed when the input is below 20%: NF-A20 PWM, NF-S12B redux 1200 PWM
and NF-B9 redux 1600 PWM

So I’ve now added a relay to be able to stop the fan. Now just got to clean this mess up befor I install it in my cabinet

Already drew up this board:

Seyude · December 30, 2023, 6:50pm

Hi @ErikNL, would it be possible to control multiple (6) of these fans with this setup?

ErikNL · January 2, 2024, 11:01am

With a ESP8266, it might be hard to work with 6 fans, since you need 2 pins per fan (1 for control, 1 to measure speed). The ESP8266 does have 17 GPIO pins, but not all are usable I believe. More info here: ESP8266 Pinout Reference: Which GPIO pins should you use? | Random Nerd Tutorials

You might be better of using a ESP32, since that does have more pins: ESP32 Pinout Reference: Which GPIO pins should you use? | Random Nerd Tutorials
You could for instance use something like a D1 mini esp32

I wasn’t able to get the board I drew up in the post above working, it’s now gathering dust until I feel the need to pick it up again

lucaxxaa · February 25, 2024, 7:17am

Hello. I try now, as you to control Noctua NF-P12 redux-1700.
Made quick test, without resistance.
What value of resistance you used and it is connected to tachometer

lucaxxaa · February 26, 2024, 10:31am

Then someone have try to use two resistors? Do you have exact value and schematic?
I am newbie

Is right this schematic, vin as output of tachimeter fan, and vout to D1 mini ?

lucaxxaa · February 27, 2024, 7:33pm

update. I use 4k resisto pull up and +3.3v on, tachometer fan pin, and it return right rpm, only with fan at 100% power. To low power, values, are not relly.
I will try 1k resistor.