DIY rack-mounted laptop

Do you have any old hardware lying around your house? I certainly do. I have an old VN7 gaming laptop that suffered a serious drop a few years back, and it was immediately replaced by a smaller, lighter machine.

The damage was in a critical spot where both the power supply and the monitor connected. As a result, it didn’t take long for it to completely fall apart after the drop:

However, this laptop had pretty decent specs for its time, so it seemed like a waste to just let it gather dust.

I already run a home assistant instance that manages also additional Docker applications. Recently, I found myself in need of a slightly more powerful machine to use as a development server. The timing couldn’t have been more perfect!

I soon discovered that server hardware is prohibitively expensive. A 1U chassis ranges from 50 to 100 EUR, which is quite costly, especially considering the additional modifications needed, like drilling extra ventilation holes. Plus, I already had some spare rack parts at home, so I decided to build one myself instead!

Shopping list

an angled C5 power cable for the laptop’s power supply: here. Being angled saves some useful space.
an angled USB micro cable to connect the monitor display here. Being angled saves some useful space.
a momentary switch like this.
a status led like this with its holder.
an arduino-compatible board, plus some headers and cables. I used an old Arduino Micro, which I had lying around. Any board will do, as long as it supports serial communication via USB.
a tiny OLED screen, like this.
2020 or 2040 aluminium profiles work magic. I used two 2040 250mm and one 2020 500mm which I cut to size.
a few corner brackets. Either external ones, or hidden ones.
a bunch of machine screws. Those can be found in various lengths here, I used mostly M3 and M5 screws in 8, 10 and 16mm lengths. And a bunch of T-nuts, like these or these.
a bunch of threaded nuts like those.
a couple of metal, wood or acrylic panels. I used one of these on one side, and a sheet of transparent acrylic I had laying around. I’ve chosen the ones made of perforated aluminium because of a few perks: it’s almost of the right size, the perforation adds ventilation for free and makes it easier to cut at home.

Tools

drill
tapping tool. If you know what that is, you may already own one. If not, it’s required to tap for M5 screw into the 2020/2040 profiles, and here’s a cheap one which could last for a couple of uses :-D (I’d suggest you get a proper one, or at least one with a longer handle).
files and something to cut metal, to cut a hole in the blank panel for the monitor.
3d printer

Planning and tests

The primary function of this machine will be to serve as a development server, which means I’ll mostly access it remotely from another computer. Additionally, it will operate various other software programs, and I want to be able to monitor the machine’s status easily.

I plan to achieve this through two methods:

Transmitting its metrics to Home Assistant using MQTT.
Utilizing a visible, physical status monitor to quickly assess the machine’s health at a glance.

Before beginning to construct the parts, I needed to verify if the monitor setup was feasible. Therefore, I decided to add some wires and give it a try.

How does it work?

A Python script performs checks on:

Disk space
CPU temperature
Available memory
Network status

This script then sends that information to the Arduino board through the serial channel. It also connects to a MQTT server which runs on Home Assistant to send it metrics about the machine.

The script runs as a service, starting at server boot, and is maintained actively.

The code on the Arduino board executes several tasks:

It receives status information via the serial channel.
It plots metrics onto a grid.
It displays icons based on the network status.
After 10 seconds of idleness, it shows a waiting page, useful if the system goes down or disconnects.
It controls an LED, turning it on or off depending on whether the host machine is transmitting data.

I might write a separate post about this in the future, as there are numerous interesting details involved.

Once connected to MQTT, I can display metrics about it in Home Assistant:

Great! Now, software works, time to build a chassis for it!

Building the chassis

The chassis is constructed by combining aluminum profiles into a sturdy frame, which will be enclosed by one metal and one acrylic panel. 3D-printed parts will close the back and secure the disk, motherboard, and power supply in place.

To try out whether the assembly was rigid enough, I assembled the two 2020, 2040 cut to size and the panel together with a few corner brackets and screws. This requires tapping the central hole of the 250mm profiles and drilling four holes in the 19” rack panel.

Regrettably, I forgot to take pictures of the entire process.

After drilling a few holes and cutting the two panels to size, here’s a preliminary look at the chassis:

Now, it was time to design some plastic parts.

For this, I traced the laptop motherboard’s outline onto paper. I measured the dimensions of both the chassis and the motherboard, then began drafting a design in Fusion 360. After a few iterations, the final render looked like this:

Final assembly

Here’s the final result with everything assembled and securely bolted: looks neat, doesn’t it?