The person who did the original hack on these says they are audible and the controller is constantly switching the fan on and off so they reconnected it to 3.3v

The person who did the original hack on these says they are audible and the controller is constantly switching the fan on and off so they reconnected it to 3.3v all the time. So it runs at a lower speed and constantly. See this link under the low noise mod heading https://github.com/Hypfer/esp8266-vindriktning-particle-sensor https://github.com/Hypfer/esp8266-vindriktning-particle-sens...