Screen Time features for NixOS.

For now, it's not a proper Nix package, just a bunch of configuration options along with a script.

Features

• Downtime: Block your computer outside of specified working hours, by terminating your user's session and sleeping the computer.
• URL Blocklist: Block specified URLs in Chromium and Firefox.

Requirements

1. Not knowing root password

In order for this system to work properly, you should not know what your root password is. Unfortunately on Linux, a lot of stuff depend on having root access. Fortunately, the stuff you need root access for is rarely an emergency. Trust me, you'll be just fine without sudo. Not to mention more secure too, depending on your configuration.

In order to achieve this and still be able to be root and do system modifications when a need arises, do the following.:

1. Timelock your root password. Set the decryption time to an amount that'll prevent your impulsive behavior. Whenever you want to make a change in your system, you can start decrypting the password. After the decryption is complete, you can do whatever system modifications you want, and then delete the decrypted password.

   I personally note down system modifications which require root access and do all of them at once every few weeks.

   I also set the decryption time to 8 hours but as you can tell from the existence of this repo, I had a pretty severe case of internet addiction. For most people, 30 mins or 1 hour will be perfectly ok.

2. Remove your user from the sudo group.

users.users.<name>.extraGroups = [ wheel ]

3. (Suggestion) Install distrobox. Distrobox allows the creation of Linux containers as easily as "distrobox enter debian". This allows you to be dropped into any Linux distribution and be able to install software on it while having screen time features active on the host machine. Also check out podman.

2. Constant connectivity

The script screentime.nu won't trust system clock unless you are online, to prevent system time modifications through BIOS. You can set a maximum allowed offline usage time as described below.

Installation

1. Clone the repository with sudo:

sudo git clone "https://github.com/rayanamal/screentime-nixos.git"

2. Set the configuration options at the start of the screentime.nu file.

You're given 3 minutes every time you boot independent of all the options.

3. Change the cloned repository's ownership to root if it's not already:

chown -R root:root /path/to/screentime-nixos/

4. Add this to your /etc/nixos/configuration.nix:

  systemd.services.screentime = {
  	wantedBy = [ "multi-user.target" ];
  	serviceConfig = {
      Restart = "on-failure";
    };
    script = "/path/to/repo/.screentime.nu";
    environment.PATH = lib.mkForce "/run/current-system/sw/bin";
  };

Edit path/to/repo/ to put the correct path to cloned repository.

5. Make sure nushell is available to the root user. You can add it with:

 environment.systemPackages = with pkgs; [
    nushell
 ]

6. Add the following to your configuration.nix. Tailor the website list for your own browsing habits.

  programs.chromium = { 
    enable = true;
    extraOpts = {
      "URLBlocklist" = [
        "news.ycombinator.com"
        "youtube.com"
        "lobste.rs"
        "reddit.com"
      ];
    };
  };

# Everything is blocked on Firefox, so that you don't use it
  programs.firefox = {
  	enable = true;
    policies.WebsiteFilter = {
      Block =  ["<all_urls>"];
    };
  };

If you prefer Firefox as your main browser, refer to the respective documentation for configuring url blocklists: Firefox, Chromium.

Screen-timing your phone

If you want to use non-bypassable Screen Time measures found in this repo for your computer, it's possible you want to use them for your phone too.

• The easiest way to do that (especially if you're in the US and don't use apps like WhatsApp) is to get a Light Phone.
• If you absolutely can't do that, then the next best solution is to give someone you trust the Screen Time password on your phone.
• If you don't have anyone you can trust (which is arguably an even bigger problem that needs fixing!), you can timelock your Screen Time password and ask someone to enter (but not remember) the Screen Time password, or you can use various bluetooth/USB keyboard emulator apps and tools on various platforms to enter the password yourself without seeing it.

Notes

Screen Time controls are subjective. Everyone has different computering habits. And there's always the (mostly justified) argument that the only reason people are not able to control their screen usage is because they lack self-awareness and/or a purpose in life to be motivated for. Self awareness can be gained through Cognitive-Behavioral Therapy, meditation, or being a devout Muslim. A purpose in life can be gained through a lot of things: your loved ones, activism of all types, the desire to improve other people's lives, even work. Though most of these crumble when faced with the question "We're all gonna die anyway, why bother?". Remarkably religions involving afterlife - specifically Islam - pass this test. Even though this accurately describes the predicament of the modern individual, it's far from the whole picture.

It's known that Big Tech companies are specifically targeting and engineering for your attention, optimizing for dopamine hits to keep the ad dollars flowing. Hundreds of millions are spent per year to A/B test some UI change, will it lead to more "engagement" or not? So it's not fair at all to put the blame on the user fully either. When you unleash algorithmic feeds on a 21th century population, inevitably a sizeable fraction gets caught in the net.

For many people, there is no need for Screen Time. They're busy enough with their daily lives. For others, a little bit of friction (think about iOS Screen Time without a password) is enough. Yet our kind, software engineers, are ironically the ones most prone to falling to bad usage habits, due to our fascination with technology, the lack of friction because of our tech-savviness, and the chronically online nature of our job. Thus the need for Screen Time controls, and the need for this project. I'm a happy user since 2 years now, and I see the positive effect on myself.

Turns out I had undiagnosed ADHD all these years. Turns out I've found ways to adapt to it and live with it. One primary way being this project.

The paragraphs striked out above are a good example of how undiagnosed ADHD leads one to have incorrect beliefs about how non-ADHD people's brains work.

Contributing and Feedback

Let me know how this project worked (or didn't) for you!

This project is open to contributions.

Notes to myself

• We can rebuild nixos with the same delay (after change of configuration.nix) that is in the password and impulse control will work without the user ever needing to unlock root access.
• Through the use of a USB-capable external device like Raspberry Pi Pico W, we can also prevent the user from changing the BIOS system time: The device can set and store the BIOS password. This would allow us to trust the system clock even when offline. Such a device can further be developed into a unified interface for holding the Screen Time PINs/root account passwords of all kinds of devices including phones. It could also enable self-hosting the timelock part in a non-compute-intensive manner by acting as a password vault and not requiring a timelock, while also supporting external backing up of these passwords in their timelocked form. It could present a UI over Wi-Fi. This device could also act as a hardware key for unlocking a LUKS-encrypted PC, preventing the user from booting the device from a live USB drive and disabling the screentime program on the PC.
• If Screen Time features are compiled into a custom Linux kernel, the user can have root access too and Screen Time features will still work. Unless the root user can change the kernel, which I believe it can. Though this will be totally overkill.