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I'm currently trying my very first schematic (in Fritzing) for a bigger project on fermentation that I'm working on as a hobby. I had no prior knowledge of electronics before this project, but am reading up on the basics, the datasheets of the different parts and I'm trying some things out. I'm a web developer, so the code part I got covered, but the electronics part is a learning process :)

But before I plug this all up, I'd like to get some feedback on my schematic, just to be sure. I did find some simpler setups, but I'd really like to use the MOSFET and Level Shifter to be on the safer side of things.

Alright, so the parts are the following: Fritzing schematic

  • Top left: power source (Belgian 230 V with grounding pin)
  • Top middle: LRS-350-12 Power supply
  • Top right: Noctua NF-A8 12V 4-pin fan with PWM
  • Middle right: MOSFET IRLB8721
  • Bottom left: ESP32 Wroom-32 DevkitV1 30 pin
  • Bottom right: Whadda Logic Level Converter module (WP1410)

Do you think this setup could work? I use the level shifter (LLC) because the datasheet said the PWM wire (blue) uses 5V and I want to be on the safe side. And the MOSFET is there for safety but also better control.

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  • \$\begingroup\$ Welcome! Why the level shifter? \$\endgroup\$ Commented Mar 31 at 11:37
  • \$\begingroup\$ Thanks! The datasheet of the Noctua said the PWM uses 5V and the ESP32 uses 3.3V signals officially. So for safety and stability. \$\endgroup\$ Commented Mar 31 at 11:44
  • \$\begingroup\$ Check the fine print. I'm almost willing to bet that it will accept 3.3 V directly. The tacho output is usually open collector so you can pull it up to whatever voltage your want. If not, voltage divider down to 3.3 V. \$\endgroup\$ Commented Mar 31 at 11:50
  • \$\begingroup\$ Yeah, the white paper on PWM by Noctua mentions that the "signal is pulled up to 3.3V/5V inside the fan", so I think it would work without the level shifter, too. I'm somewhat cautious because I'll be using longer cables eventually. Maybe I'm a bit too cautious? \$\endgroup\$ Commented Mar 31 at 12:00
  • \$\begingroup\$ 1) Never ever connect the Earth of the AC supply (which is the one as GND on PS1) to the signal GND (on ESP32); 2) ESP32 GND as well as the level shifter GND need to connect to V- of the Power supply. 3) if the white paper you mentioned is refer to this one, then your Noctua Connector does not match the one shown on the white paper. 4) the level shifter only work if you have VH connect to the high side of the power (which I assumed is 5V), and the VL need to be connect to ESP32 3.3v. \$\endgroup\$ Commented Mar 31 at 12:17

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