Central Core Unit

Central Core Unit

For the Smart Home on Wheels project to work, everything has to be controlled by a central core unit. I’ve gone back and forth, trying to figure out a way to do it affordably and still have enough power to control everything. openHAB has been narrowed down as the best choice for software, leaving us to figure out the best way to run that software. The benefit is that openHAB will run on a variety of hardware and operating systems so we have options.

Ubuntu OS

The benefit of Ubuntu is simple, it is free, not overly demanding, runs on a lot of hardware, and is updated frequently. There are server and desktop versions, so if we don’t want to run a GUI like Windows or macOS, we don’t have to. Because of the varied demands of the central core unit though, I may just install the desktop version anyway so I have access to the GUI if need be. Once that is installed on the hardware and all the server apps are installed, we will hopefully not have to log into it directly and can do everything through a terminal or remote desktop.

Plex Media Server

After we install Ubuntu, we can set up Plex Media Server. Plex runs on Ubuntu, so there should be no problem doing this. We have a large media library of about 3.5TB which is currently stored on an external USB 3 drive, which we will be transferring over to an internal hard drive in the final setup. With Ubuntu, we should be able to set up a RAID system, so we can have two internal hard drives backing up from one to the other so we never lose data.

File Sharing

Its easy to set up a Linux box to share directories over a network with macOS computers through netatalk. In the central core unit, we’ll add one hard drive, it can be as low as 2TB, to back up everything we have on our computers and even cloud drives to keep everything safe. Another easy step with Ubuntu.


Because openHAB works on Ubuntu, it’ll be great as a central machine. The rules can be controlled via a tablet app, so once set up, we shouldn’t have to access the app directly. However, because much of openHAB in our case will use Z-Wave devices, we do need a Z-Wave receiver/transmitter. Those aren’t terribly expensive, around $40, and can be plugged into a USB port. Other devices that don’t use Z-Wave may be more complicated, but some use Wifi, some use proprietary hardware. What we need exactly depends on what we will end up using for smart devices.

The Hardware

The options are endless. Find a device that meets size, power demands, and power output. Hopefully it can be upgraded so things can improved if needed. We’ve looked at the Raspberry Pi, Byte, Azulle, Intel, dedicated smart home hubs like Wink and Samsung. Factoring in cost and power, we settled on something else. Searching the various craigslist sites wherever we happened to have some contact, we found the device that we wanted. An older Dell 1U rack mount server. Its older, about 9 years old, but it can run 2 quad-core Xeon processors, 24GB of RAM, has space for four internal hard drives, and is only $50. We just have to get it to us. If all goes well, our contact in that city will be picking it up tomorrow and we’ll be able to get it in the next few weeks. As it is, it works. But it can be better.

For one thing, we need to add another processor. Right now, the unit only has one processor and we can get a second one for about $30. This particular server needs a fan replaced as well, but that is only about $15. It has one hard drive with 320GB, which is fine for the Ubuntu OS and adding apps, but we will likely upgrade that to a small SSD. It also only has two USB 2 ports, but we can buy a small USB 3 card to add faster speeds to that. It also has the benefit of having gigabit ethernet since it will always be plugged in, we won’t need wifi for it. I have also checked out prices for adding RAM, and boosting it from its current 8GB to its max of 24GB, it would be about $45. Adding it all together, we could spend $140 total and have a pretty nice system.

The only drawback is the size. A rack mount server can be pretty large, but this is only 1U. We can get a vertical rack hanger so the server will rest flush against a wall, taking up very little space. It’ll be out in the open, but that can be okay. It will have enough air flow to keep it cool, so it should all work.

Tomorrow we will know more, but we should have a rack mount server somewhere we can pick it up at a later date. Its not the easiest solution for end users, but recycling old computers is one of the best ways to deal with this project and keep its total cost down.

Written by 

Eric is a dedicated technophile and strives to make things in Sleipnir as innovative, simple to use, and convenient as possible. He has worked a variety of jobs, from construction and manufacturing to working as a civilian in a law enforcement agency. He is an avid tabletop gamer and builds websites in his spare time.

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