Summary

DIY inspired by Vektiva SmarWi product from Czech Republic. It can open and close window ventilation with wifi commands. Can be customized for Smart Homes systems.

YouTube video

https://youtu.be/Q-FsNvmDmAk

Characteristics:

Arduino Wemos D1 Mini (Wi-Fi 2.4 GHz)

Very powerful 35 RPM motor with gearbox (and with "self-locking" function)

Can be tweaked for almost any window

For 9-15V power supply

Adjustable stop switch for closing

Open time and speeds can be customized via webpage

Basic Arduino code attached (you need to specify ESSID and wireless key inside it)

No cloud (public IP and portforward needed for remote control from internet)

Physical button (if you do not have Wi-Fi or for emergency control)

It is a little noisy (not suitable for night time)

It should be glued or drilled to both window and window frame

Commands:

There is no password for this moment!

http://IP_ADDRESS/ (settings and status)

http://IP_ADDRESS/open (open window)

http://IP_ADDRESS/close (close window)

http://IP_ADDRESS/unload (if you want to fully open window or dismantle everything)

Shop list:

Motor 12V (~35RPM):
https://www.aliexpress.com/item/33036140291.html (~35RPM and 6 mm shaft without hole, more RPM is faster but weaker, less RPM is slower and more powerful)

Endswitch and button switch:
https://www.aliexpress.com/item/4000638059196.html

Arduino Wemos D1 Mini:
https://www.aliexpress.com/item/32787418018.html

Motor driver TB6612FNG:
https://www.aliexpress.com/wholesale?catId=0&SearchText=tb6612fng (Order carefully! I repeatedly received wrong board DRV8833 without PWM function.)

RJ45 port:
https://www.aliexpress.com/item/32974903992.html (I ripped one from my old wifi router)

DC power jacks:
https://www.aliexpress.com/item/4000907311371.html

White button cable:
https://www.aliexpress.com/item/33026678139.html (between main unit and button unit)

2x 47k resistors:
https://www.aliexpress.com/item/1005001437008358.html

Cable window holders:
https://www.aliexpress.com/item/1005001436039914.html

Software

"Arduino IDE v1.8.x" is needed:
https://www.arduino.cc/en/software

Windows Drivers for "Wemos D1 Mini" is needed:
https://www.wemos.cc/en/latest/ch340_driver.html

Install ESP8266 package into IDE:
Enter https://arduino.esp8266.com/stable/package_esp8266com_index.json into the File > Preferences > Additional Boards Manager URLs field of the Arduino IDE
In the board manager search for "esp8266" package and install this older version: 2.5.0

Select "LOLIN (Wemos) D1 R2 mini" at Tools > Board
Select your Wemos serial port at Tools > Port
Change this settings: Tools > FlashSize to "4M (2M SPIFFS)"
Download and open INO source file from this Thiginverse project
Change your wifi settings at line 12 and 13
Compile with Project > Upload
Wait for 100%
Check assigned IP address with Tools > Serial Monitor or from your home wifi router settings

Some thoughts

Do not tighten comb piece to much. It should be a little loose to tilt down with window.