OpenLock_project

An extremely lightweight background app initially built using Claude for cooperative screen time limitation & app blocking on a Windows PC.

It blocks a list of programs you choose, during a time window you choose, and can start automatically when you log in.

This is for self-imposed limits, not for blocking a determined user or adversary. Anyone with admin access (likely you) can stop the script, end the scheduled task, or edit the config — there's no anti-tamper protection. It works because you've agreed to the rules, not because it's unbreakable.

Files

• screen_lock.py — the script that does the blocking
• config.json — your list of blocked apps + the time window
• setup_autostart.ps1 — one-time setup to run it automatically at login
• screen_lock.log — created automatically; shows what got blocked and when

Requirements

• Python 3.10+ installed on Windows, with the psutil package:

  pip install psutil
  

1. Configure what to block

Open config.json in any text editor. Example:

{
  "blocked_apps": [
    "steam.exe",
    "C:\\Users\\YourName\\AppData\\Local\\Discord\\Discord.exe"
  ],
  "start_time": "09:00",
  "end_time": "17:00",
  "check_interval_seconds": 5
}

• blocked_apps: each entry is either:

  • just the executable name (e.g. "steam.exe") — blocks it no matter where it's installed, or
  • a full path (e.g. "C:\\Program Files\\App\\app.exe") — blocks only that specific install.

  To find an app's exe name or path: open Task Manager → right-click the running app → "Open file location". The address bar shows the full path.

• start_time / end_time: 24-hour HH:MM format. The window can cross midnight (e.g. "22:00" to "06:00" blocks overnight).

• check_interval_seconds: how often (in seconds) it checks for blocked apps and the current time. Lower = more responsive, slightly more CPU use. 5 seconds is a sensible default.

You can edit config.json and save it any time — the running script picks up changes automatically within one check interval, no restart needed.

2. Test it manually first

Before setting up auto-start, run it directly to make sure it behaves as expected:

python screen_lock.py

Try opening a blocked app during the blocked window — it should close within check_interval_seconds. Check screen_lock.log to see what happened. Press Ctrl+C to stop.

3. Set up auto-start at login

1. Right-click setup_autostart.ps1 → "Run with PowerShell" (or open PowerShell as Administrator, cd to this folder, and run .\setup_autostart.ps1).
   • If PowerShell blocks the script with an "execution policy" error, run this first in an admin PowerShell window:

     Set-ExecutionPolicy -Scope CurrentUser -ExecutionPolicy RemoteSigned
     

2. This registers a Task Scheduler task named ScreenTimeLock that starts the script automatically every time you log in, runs it silently in the background (no console window), and restarts it if it crashes.
3. To start it immediately without rebooting:

   Start-ScheduledTask -TaskName "ScreenTimeLock"
   

Removing it

To stop auto-start entirely:

Unregister-ScheduledTask -TaskName "ScreenTimeLock" -Confirm:$false

To pause blocking temporarily without removing it, just end the running "pythonw.exe" process in Task Manager, or edit config.json to set a time window that doesn't apply (e.g. start_time and end_time both "00:00").

Known limitations

• Closes blocked apps abruptly (like ending a task) — any unsaved work in that app will be lost. Save before the blocking window starts.
• Does not block browser-based access to websites — only native .exe programs. If your target is a website rather than an app, you'd need a different approach (e.g. hosts file edits or browser extensions).
• Does not survive Safe Mode, and can be disabled by anyone with admin rights on the machine — by design, since this is meant to be cooperative.