Let's make the Ikea Foernuftig air filter a little smarter. Here is the matching completely over-engineered firmware.

ESP32 - Mini D1
StepDown +5V converter
Ikea Foernuftig
and a few wires

Clone this repository and open it with platformIO. Remember, the SPIFF must also be flashed. On a terminal in vscode you can do it with

pio run -t uploadfs
pio run -t upload

After that, take a look at your monitorport ...

[I][wificlient.cpp:91] wificlient_Task(): Start Wifi-Client on Core: 1
[I][wificlient.cpp:108] wificlient_Task(): WiFi connection lost, restart ... 
[I][wificlient.cpp:398] wificlient_start_softAP(): starting Wifi-AP with SSID "foernuftig_d1fd28" / "foernuftig"
[I][wificlient.cpp:399] wificlient_start_softAP(): AP IP address: 192.168.4.1
[I][ntp.cpp:65] ntp_Task(): Start NTP Task on Core: 1
[I][mqttclient.cpp:267] mqtt_client_Task(): Start MQTT-Client on Core: 1
[I][webserver.cpp:56] asyncwebserver_Task(): Start Webserver on Core: 1
[I][callback.cpp:31] callback_print():  |
[I][callback.cpp:32] callback_print():  +--'mqtt client' ( 0x3ffb961c / 1 )
[I][callback.cpp:34] callback_print():  |  +--id:'foernuftig', event mask:0003, prio: 2, active: true
[I][callback.cpp:31] callback_print():  |
[I][callback.cpp:32] callback_print():  +--'webserver' ( 0x3ffb9670 / 8 )
[I][callback.cpp:34] callback_print():  |  +--id:'/foernuftig.htm', event mask:001f, prio: 2, active: true
[I][callback.cpp:34] callback_print():  |  +--id:'/button.htm', event mask:001f, prio: 2, active: true
[I][callback.cpp:34] callback_print():  |  +--id:'/index.htm', event mask:0007, prio: 1, active: true
[I][callback.cpp:34] callback_print():  |  +--id:'/wlan.htm', event mask:001f, prio: 3, active: true
[I][callback.cpp:34] callback_print():  |  +--id:'/update.htm', event mask:0007, prio: 3, active: true
[I][callback.cpp:34] callback_print():  |  +--id:'/info.htm', event mask:0007, prio: 3, active: true
[I][callback.cpp:34] callback_print():  |  +--id:'/ntp.htm', event mask:001f, prio: 2, active: true
[I][callback.cpp:34] callback_print():  |  +--id:'/mqttclient.htm', event mask:001f, prio: 2, active: true

When the output look like this, congratulation!

After the first start an access point will be opened with an unique name like

foernuftig_XXXXX

and an not so unique password

foernuftig

After that you can configure the foernuftig under the following IP-address with your favorite webbrowser

http://192.168.4.1

step 1:remove the two cover screws
step 2:remove the cover plate
step 3:remove the nut
step 4:remove the two pcb screws
step 5:remove the two connectirs
step 6:remove the controller IC

step 8: connect the StepDown +5V converter to 24V and GND and adjust them to +5V

• supply: +24V power supply control for the fan. high mean on and low means off
• CLK: fan control signal, PWM with 50/50 duty cycle, 100Hz means 100rpm
• FG: fan feedback signal: PWM with 50/50 duty cycle, 100Hz means 100rpm
• LED: status LED, currently not working. need resistor change
• switch pin 0..3: switch pin, cycles from 0001 to 1000. 4 stages

+24V ( PCB ) -> IN+ ( StepDown converter )
GND ( PCB ) -> IN- ( StepDown converter )

and

OUT+ ( StepDown converter ) -> VCC ( ESP32 )
OUT- ( StepDown converter ) -> GND ( ESP32 )

GPIO19 ( ESP32 ) -> supply ( IC U1 )
GPIO18 ( ESP32 ) -> CLK ( IC U1 )
GPIO33 ( ESP32 ) -> FG ( IC U1 )
GPIO35 ( ESP32 ) -> LED ( IC U1 )

GPIO21 ( ESP32 ) -> switch pin 0 ( PCB )
GPIO22 ( ESP32 ) -> switch pin 1 ( PCB )
GPIO32 ( ESP32 ) -> switch pin 2 ( PCB )
GPIO25 ( ESP32 ) -> switch pin 3 ( PCB )

Reminder: All pins can also be changed later via web interface.

Every Contribution to this repository is highly welcome! Don't fear to create pull requests which enhance or fix the project, you are going to help everybody.

If you want to donate to the author then you can buy me a coffee.