Mate Smart Lock automatically locks and unlocks your Linux screen when your smartphone moves away. A modern, lightweight alternative to BlueProximity with no heavy dependencies.
Executive Summary
Mate Smart Lock is a Linux application that uses your smartphone's Bluetooth as a proximity key: when you walk away from your computer, the screen locks automatically. When you return, it unlocks. Built out of personal need, published as open source on GitHub and the Snap Store.
Problem
The only existing project doing this (BlueProximity) had been abandoned for over a decade and was incompatible with Python 3. No working alternative existed for the MATE Desktop environment.
Solution
I built a lightweight GTK3 app from scratch using standard Linux tools (bluetoothctl, loginctl) with no heavy dependencies. Configurable, with system tray icon and custom command support.
Results
- Published on Snap Store and as a .deb package
- Open source on GitHub with documented code
- Zero external dependencies — uses only system tools
- Configurable with tolerance thresholds and custom commands
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Mate Smart Lock
Automatically lock and unlock your Linux screen using your smartphone as a proximity key.
I have been using Ubuntu MATE as my primary desktop for years. At some point, I looked for an app that would automatically lock the screen when I walk away from the computer, using my smartphone’s Bluetooth as a “proximity key.” Simple concept: if the phone is near, the screen is unlocked. If I walk away, it locks itself.
The only project that did this was called BlueProximity: abandoned for over a decade, incompatible with Python 3, and practically unusable on modern systems. No working alternative existed for the MATE desktop.
Finding nothing usable, I decided to build it from scratch. Mate Smart Lock is the result: a lightweight, modern, configurable GTK3 app that uses standard Linux tools (bluetoothctl, loginctl) without heavy dependencies or additional services.
Features
🔒 Auto-locks itself
When you leave home or step away from your desk, your phone disconnects and your screen locks. You don’t have to do anything.
🔓 Unlocks when you return
Come back, your phone reconnects, and your computer is already unlocked waiting for you. Optional, requires a small system configuration.
⏱ No false alarms
Bluetooth sometimes loses signal for a second – it happens. You can set a tolerance margin before the screen actually locks.
🖥 Always a click away
A system tray icon gives you quick access to settings and lets you lock or unlock manually with a single click.
⚙️ Your way
You are not forced to use the default commands. From the Advanced tab, you can replace them with any script or command you need.
🪶 Truly lightweight
No daemons installed, no network ports opened, no RAM wasted. It only uses tools already present on your system.
Screenshots
Installation
⚡ Snap Store (recommended)
Available on the Snap Store. Automatic updates included.
sudo snap install mate-smart-lock📦 Debian / Ubuntu (.deb)
Download the .deb package from the GitHub releases page and install it with:
sudo dpkg -i mate-smart-lock_0.1.0_all.deb
sudo apt-get install -fPrivacy & Security
No accounts, no internet connection, no data sent anywhere. The app runs entirely on your computer, only talks to Bluetooth and the session manager. Your settings stay in a local file – that’s it.
Open Source
The code is open, free, and on GitHub. Feel free to explore, contribute, or just see how it works.
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