Computers are amazing — they are the ultimate universal tools. But sometimes modern interfaces, ads and social algorithms are exactly what gets in the way of getting things done. Luminum turns a Raspberry Pi into a space for focused work and learning.
What it is
The device starts up into a menu and nothing else. There is no desktop underneath it, no browser to wander off into. What is on the menu is what you set up there.
There are two accounts: an admin account (luminer), holding the password and the right to install things, and an everyday account (luminee) with neither. Apps run as the everyday account. Every way out of the menu — adding an app, changing the WiFi, reaching a desktop — asks for the admin password first.
Apps come from the app library, and each one is described by a short YAML file called a recipe. You can write a custom recipe to whitelist something that is not yet in the library.
What you need
- A Raspberry Pi (4 or 5 recommended; a 3 works for the lighter apps)
- A microSD card, 16 GB or larger — everything on it will be erased
- A card reader on the computer you are writing from
- A screen with HDMI, a keyboard and a mouse
- Your WiFi name and password — needed to install apps, though many apps then work offline
A wired USB keyboard makes the first boot easier. A Bluetooth keyboard works too, but you will need something plugged in to pair it with.
1. Write the SD card
-
Download the Luminum image. It is a single
.img.xzfile of about 2 GB. Get Luminum -
Install Raspberry Pi Imager from raspberrypi.com/software. It runs on Windows, macOS and Linux. Balena Etcher works just as well if you already have it.
-
Write the image. In Imager, choose Use custom under the operating system list and pick the file you downloaded. Choose your SD card under storage. Write.
Imager will offer to apply its own settings — hostname, username, WiFi, SSH. Skip that (choose No when asked to apply OS customisation). Luminum sets up its own accounts on first boot, and Imager's settings will conflict with them.
-
Put the card in the Pi, connect the screen, keyboard and mouse, then plug in the power.
2. First boot
The first boot takes a few minutes: the Pi expands the card, creates the two accounts and reboots itself once before setup appears. A blank or busy screen for a minute or two at this stage is normal.
Setup is a plain text screen driven by the keyboard: arrow keys to move,
Enter to choose, Tab to move between fields. There is
no mouse yet.
Set the admin password
This is the admin password. It is what you type to open admin mode later, and
it is the only thing standing between the menu and the rest of the machine. If
you are setting the device up for someone else, this is your password, not
theirs — pick something they will not guess and do not type it in front of
them. Minimum six characters; Ctrl+R reveals what you typed.
Join WiFi
Pick your network from the list and enter its password, or choose I use a
wired (Ethernet) connection at the end of the list. Ctrl+R rescans
if your network is missing. A connection is needed to install apps; once
installed, many apps work without one.
Pair Bluetooth devices
If you use a Bluetooth keyboard, mouse or speaker, put it in pairing mode and pick it from the list. Otherwise skip this step — you can pair devices later from admin mode.
Done
Setup reports that it is finished and restarts the Pi. From this point the Pi starts up straight into the menu, automatically, with no login prompt. The menu is empty apart from Add App until you add something.
3. Add the first app
- Choose Add App at the bottom of the menu and enter your admin password.
- The app library opens. The list of available apps is on the left; the description of the highlighted one is on the right, with the age it suits and what it needs.
- Press
Enteron an app to open its setup.
- Fill in whatever the app asks for. Most need nothing; the Website app needs an address.
- Try installs the app for your own account and runs it, without putting it on the menu. Use it to check an app behaves before whitelisting it.
- Install installs it properly and adds it to the menu. Installing downloads packages, so it can take several minutes; the output is shown as it runs.
When the install finishes, the app library closes and the menu reappears with the new entry on it.
Everyday use
From here on, the device is the menu. It starts into it with no login prompt,
shows the clock and the apps you whitelisted, and returns to it whenever an app
is quit. Arrow keys move, Enter opens. There is nothing else to
reach and nothing to close.
Two doors lead out of it, both behind the admin password: Add App at the
bottom of the menu opens the app library, and Ctrl+A opens admin
mode for the machine's own settings.
| Task | How |
|---|---|
| Add an app | Menu → Add App, then your password |
| Open admin mode | Ctrl+A from the menu, then your password |
| Change WiFi or go wired | Admin mode → Configure Internet Access |
| Pair a device | Admin mode → Pair Bluetooth Device |
| Full desktop | Admin mode → Launch GUI, for admin tasks that need one |
| Update Luminum | Admin mode → Check for Luminum Updates |
| Update the operating system | Admin mode → Update OS |
| Second screen | Ctrl+Alt+F2 for a second menu, Ctrl+Alt+F1 to go back |
| Shut down | Pull the power once the app has been quit and the menu is showing |
Adding your own books and files
The device has a shared folder, /home/luminum, that both accounts can read.
Books dropped into its library folder appear in the Library app. The easiest
way in is admin mode → Launch GUI, which gives you a normal desktop with a
shortcut to that folder.