I'm maintaining a Raspberry Pi 4 Model B (4GB) to host some tools & applications at home.

- [Deconz](https://github.com/dresden-elektronik/deconz-rest-plugin) (Zigbee gateway software of [Conbee](https://phoscon.de/en/conbee))
- [Homebridge](https://homebridge.io/) (A bridge to define non-Homekit accessories to Homekit)
- [AdGuard Home](https://adguard.com/tr/adguard-home/overview.html) (Personal DNS server to block ads at the DNS level)

I've heard some CPU temperature problems at first, so in the first installation, I've bought [this aliminium heat sink case](https://www.kiwi-electronics.nl/aluminium-heatsink-behuizing-voor-de-raspberry-pi-4?search=heat%20sink%20case&description=true).

<center><img src="https://i.imgur.com/YvQNnMF.jpg"></center>
<center><sup>Image is taken from [kiwi-electronics listing page](https://www.kiwi-electronics.nl/aluminium-heatsink-behuizing-voor-de-raspberry-pi-4?search=heat%20sink%20case&description=true)</sup></center>

It looks quite cool and includes double fans to make sure the temperature of Pi in acceptable levels. However, after running this case and the fans a couple of days, I was disturbed by the level of noise of the fans. It creates a lot of noise. I store pi in the closed cabinet (working headless) below a closed door in the first floor. (I sleep in the second floor, yet, I can still hear the sound of the vibration created from the fans at nights.)

After running a couple of weeks like that, I see that the CPU was running around 38°, 40°. I also observed CPU load and ram usage, and it was all perfect. Since the RPi 4b is quite powerful, CPU load stays around %1-%5, and memory usage was like 10% at most. So I've decided to stop the fans. That made the Pi perfectly quite but the temperature is stable around 48°-50°, which is also acceptible.

However, I don't want to run Rpi more than 60°, so I'll be observing the temperature levels more. I've setup a couple of scripts for that, but also I've added a new "automation" rule to get notified if the CPU temperature passes a certain degree.

<center><img src="https://i.imgur.com/BP4HsQV.png"></center>

#### Homekit automations
****

I consolidate all my smart home appliances at Homekit so that I can manage all my automations in one place. (By the way, that's a good thing to do, since almost every brand want to force their automation structure, and it becomes a mess when you manage automations in different places.)

What I need for this specific automation are:

- When Raspberry Pi CPU Temperature passes a certain degree (Trigger)
- Switch on the lights, dim to 100%, and make the light red on my workspace (Action) (Hue light bulbs)
- (If I am at the workspace) (Condition) (Via a tilt sensor on the chair.)

Normally, this kind of automation is not supported at the Apple Home app, however, Homekit specs support this. So, by using [Eve app](https://www.evehome.com/en/eve-app), I can accomplish this. (The app is free to use, works on the top of Homekit.)

However, there was one small problem, I need to expose RPi temperature to Homekit. Fortunately, this could be done via [a homebridge plugin](https://www.npmjs.com/package/homebridge-raspberrypi-temperature), exposes CPU temp. into Homekit.

Now that, I have everything I need, here are the steps:

| Operation                                                    | Action |
|--------------------------------------------------|---------------|
| Set scene                              |   ![step1](https://i.imgur.com/9OdBDKV.jpg)        |
| Add trigger                            |   ![](https://i.imgur.com/OtT8oIf.jpg) |
| Add condition                          | ![](https://i.imgur.com/wkxL528.jpg) |
| Final result                                   | ![](https://i.imgur.com/QeFXOVD.jpg) |
***

All set. :)

#### Smart-Home Community
***

We have [Smart Home](https://hive.blog/created/hive-102496) community in place for a while. Feel free to share your own experience and adventures on the topic.