If the fan is connected to the 5V and GND pins then they are not controlled by software. Those two pins are directly connected to your power supply, so as long as the power supply is connected and turned on at the wall socket your fan will continue to run.

Question

How to turn off Rpi4B case’s cooling fan without pulling the power plug?

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Answer

There are many ways, including the following:

(1) Get a case with a manual power switch (Reference 2).

(2) DIY a manual cable power switch (Appendices A to C).

(3) Using Rpi GPIO to control a software switch to turn on/off the power supply for the cooling fan (Ref 6, Appendix C)

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Discussions

Discussion Notes #1 – 2019oct04 hkt1635

The OP commented that my answer does not meet his requirement, which is summarized below:

Lying in bed, after watching a movie, shut down the Rpi as a PC, without leaving the bed. Therefore a local switch near the Rpi but too far from bed won’t do.

Now let me consider some cases and see if I can product a real solution.

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Case 1 – The OP sits in front of Rpi on a desk, starts the VLC Media Player, selects a movie, then walks to his bed, lies on bed and starts watching the movie. He does not want to leave the bed anymore, and wishes NOT to get up and walk to the wall socket to switch off the wall wart.

Now either he changes his present Rpi case without a manual power switch to a new one with manual power switch, or DIY his own switch, IF the switch is “local” to Rpi but remote from bed, then he has to get up to reach the switch.

In other words, if the switch either comes with the Rpi case, or DIY inserted, does NOT solve the problem.

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Case 2 – I have thought about a couple of more possible solutions, including the following:

(2.1) Use a mobile phone to switch Rpi, and then case power,

(2.2) Use a remote controller (similar to TV remote) to switch off Rpi and then case power, or just cooling fan power, which is easier.

(2.3) Lengthen the power cord at either or both ends of the manual power switch (Appendix A, Tamiya socket labelled “B”). This way, the OP needs to carry the switch with a dangling long power cord to bed. But this method is easy. One problem is that Rpi won’t be properly shutdown.

(2.4) use a WiFi power socket, …

(2.5) Extract the two wires connecting to the fan, extend the wires and added manual switch. This is easy but messy.

I need to ask the OP to confirm if I indeed understand his situation, before I suggest more solutions.

Discussion Notes #2 – 2019oct05 0938

Case 3

(3.1) Use a USB powered cooling fan, extend the USB cable to bedside, and without leaving the bed, just pull the USB plug to turn off the fan (Ref 7). This 40mm cooling fan is brushless, double bearing, and might be much more quiet than your Rpi case’s built in fan. You can also find “magnetic” bearing which is even more quiet.

(3.2) And you can add temperature sensed PWM fan speed control, so if the Rpi is not playing video, Rpi becomes cool, the fan will automatically run at very low speed, or even stops. Now you can have a nice sleep, …

/ to continue, …

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References

(1) Rpi4 Case without manual power switch

(2) Rpi4 Case with a power switch

(3) The manual power switch to DIY

(4) 250V 3A ~ 5A manual power switches

(5) How to strip the power wires

(6) Using LM2596 and LM2941 to switch on/off PSU/currenct

(7) Amazon 40mm x 10mm 5VDC USB Brushless Cooling Fan, Dual Ball Bearing – $14/2 pcs

(8) Sonoff Smart Remote Control Wifi Switch Compatible with Alexa Iphone Android – $22

(9) Sonoff Product Info

(10) Sonoff User Guide

(11) Six Sonoff Secrets: Storage, Safety, Switches, Sensors, Software, and Sites

(12) Sonoff Basic WiFi Smart Switch Review (YouTube)

(13) How to Use MQTT With the Raspberry Pi and ESP8266 – Thomas Varnish

(14) Make your own Sonoff WiFi switch using ESP8266 and MQTT 2017aug09

(15) Sonoff / Tasmoto Garage Door sensors

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Appendices

Appendix A – Power Switch DIY Notes 1 – Cutting power cord to insert switch

Appendix B – Power Switch DIY Notes 2 – Switch inserted

Appendix C – Rpi4B + PSU – Power Switch Testing OK

Appendix D – Using A Software Switch to switch on/off cooling fan power

Appendix E – Sonoff Smart Remote Control Wifi Switch

Product Spec

Supports 2.4G WIFI router and 2/3/4G mobile network (5G router not supported)

Power Input – 90 ~250VAC

Maximum load current – 10A

Only use “eWeLink” free app.

Security Mechanism: WEP/WPA-PSK/WPA2-PSK

Features

Remote ON/OFF: Turn electrical devices on/off from anywhere

App Support: Free IOS and Android mobile App eWelink

Sync Status: Real time device status provided to App

Timing: Set scheduled/countdown timers to turn on/off at specified time

Scene: Turn on/off a gang of devices one tap

Smart Scene: Trigger on/off by temperature, humidity or other environmental conditions

Control Options

Voice Control

Sonoff Basic Switch works with Amazon Echo,Echo Dot,Amazon Tap and Google Home to manage your devices through Voice control

Remote Control

Sonoff Switch transmits data to a cloud platform through the Wi-Fi Router, which enables you to remotely control the connected appliances, via free eWeLink App.You can download the iOS version in App Store and the Android version in Google Play.The App eWeLink enables you to control your devices easily

Timer Control

Set timing schedules for the appliances, which can include countdown, scheduled on/off

Setup Guide

1. Switch off electricity source
2. Open the covers at both ends
3. Connect the two electricity source cables (Live and Neutral) to the ports with “IN” mark, one cable for one port, and there’s no limitation for which port to connect
4. Connect the two appliances cables(Live and Neutral) to the two ports with “OUT” mark, one cable for one port, and there’s no limitation for which port to connect make the cover install firmly

End of Answer

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