ESP32 fan controller with MQTT support

This project describes how to use an ESP32 microcontroller for controlling a 4 pin fan (pwm controlled fan). Main features are:

• mode 1 (pwm mode): directly setting fan speed via pwm signal

• mode 2 (temperature controller mode): fan speed automatically increases if temperature is getting close to or higher than target temperature. Of course temperature can never get lower than air temperature of room.

• measurement of fan speed via tacho signal

• measurement of ambient values via BME280: temperature, humidity, pressure

• support of MQTT

• support of OTA (over the air updates of firmware). Please see Wiki: 06 OTA Over the air updates

• TFT display for showing status information, different resolutions supported (tested with 320x240 and 160x128)

• TFT touch display for setting pwm or target temperature

• optional: integration into home automation software openHAB

Even if you don't want to use all of these features, the project can hopefully easily be simplified or extended. With some minor modifications an ESP8266 / D1 mini should be usable.

I did this project for having an automatic temperature controller for my 3D printer housing. But of course at least the ideas used here could be used for many other purposes.

For more information please see the Wiki

Operation modes

You can operate the ESP32 fan controller mainly in two different modes, depending on your needs:

mode	description	how to set PWM	how to set actual temperature	how to set target temperature
pwm mode	fan speed directly set via PWM signal	MQTT, touch or both	BME280 (optional, only used for information)
temperature controller mode	automatic temperature control fan speed is automatically set depending on difference between target temperature and actual temperature		MQTT or BME280	MQTT, touch or both

In both modes, a TFT panel can optionally be used for showing status information from the fan, ambient (BME280: temperature, humidity, pressure) and the chosen target temperature. Different resolutions of the TFT panel are supported, layout will automatically be adapted (tested with 320x240 and 160x128).

If you use a TFT touch panel, you can set the PWM value or target temperature via the touch panel (otherwise you have to use MQTT).

For more information please see the Wiki: 03 Examples: operation modes and breadboards

Wiring diagram for fan and BME280

For more information please see the Wiki: 01 Wiring diagram

Part list

Function	Parts	Remarks	approx. price
mandatory
microcontroller	ESP32	e.g. from AZ-Delivery	8 EUR
fan	4 pin fan (4 pin means pwm controlled), 5V or 12V	tested with a standard CPU fan and a Noctua NF-F12 PWM for a list of premium fans see https://noctua.at/en/products/fan	20 EUR for Noctua
measuring tacho signal of fan	- pullup resistor 10 kΩ - RC circuit: resistor 3.3 kΩ; ceramic capacitor 100 pF
power supply	- 5V for ESP32, 5V or 12V for fan (depending on fan) or -12V when using AZ-touch (see below)	e.g. with 5.5×2.5 mm coaxial power connector	12 EUR
optional
temperature sensor	- BME280 - 2 pullup resistors 3.3 kΩ (for I2C)	e.g. from AZ-Delivery	6.50 EUR
optional
TFT display (non touch)	1.8 inch 160x128, ST7735	e.g. from AZ-Delivery	6.80 EUR
TFT touch display with ESP32 housing	AZ-touch from AZ delivery including voltage regulator and TFT touch display (2.8 inch 320x240, ILI9341, XPT2046)	e.g. from AZ-Delivery (you can also use the older 2.4 inch ArduiTouch)	30 EUR
connectors for detaching parts from AZ-touch	- e.g. 5.5×2.5 mm coaxial power connector male - JST-XH 2.54 mm for BME280 - included extra cables and connectors in case of Noctua fan

Other TFTs can most likely easily be used, as long as there is a library from Adafruit for it. If resolution is smaller than 160x128 it might be necessary to change the code in file tft.cpp. Anything bigger should automatically be rearranged. If you want to use touch, your TFT should have the XPT2046 chip to use it without any code change.

Software installation

If you're only used to the Arduino IDE, I highly recommend having a look at PlatformIO IDE.

While the Arduino IDE is sufficient for flashing, it is not very comfortable for software development. There is no syntax highlighting and no autocompletion. All the needed libraries have to be installed manually, and you will sooner or later run into trouble with different versions of the same library.

This cannot happen with PlatformIO. All libraries will automatically be installed into the project folder and cannot influence other projects.

If you absolutely want to use the Arduino IDE, please have look at the file "platformio.ini" for the libraries needed.

For installing PlatformIO IDE, follow this guide. It is as simple as:

• install VSCode (Visual Studio Code)
• install PlatformIO as an VSCode extension
• clone this repository or download it
• use "open folder" in VSCode to open this repository
• check settings in "config.h"
• upload to ESP32

Images

ArduiTouch running in "temperature controller mode"

Images of ESP32 fan controller used in a 3D printer housing

For more information please see the Wiki: 04 AZ‐touch / ArduiTouch