SignalLock
TREN
Download

macOS · Windows · Linux

Your computer locks itself when you walk away.

A small, calm menu bar app that uses Bluetooth proximity to lock your computer the moment you leave. No cloud, no account, no location tracking — everything runs locally on your device.

DownloadHow it works
Open source · GPL-3.0

01 — 03

Three steps. Then forget about it.

Set it up once. After that it stays out of your way.

  1. 01

    Choose your trusted device

    Pick your phone, AirPods, smartwatch, or a BLE tag from the menu bar.

  2. 02

    SignalLock monitors proximity

    It tracks the device's signal and visibility in the background using a moving average.

  3. 03

    Your computer locks when you move away

    Once the device leaves range and your configured delay elapses, your screen is locked automatically.

Features

As small as you'd expect from a menu bar app; as careful as you'd expect from a security tool.

  • Bluetooth proximity detection

    Tracks your trusted device's signal strength using a moving average.

  • Automatic lock

    Locks your screen in the background — fast, silent, reliable.

  • Menu bar control

    Everything lives in a small menu bar / system tray icon. No window to manage.

  • Trusted device selection

    Pick exactly which BLE device acts as your key.

  • Adjustable sensitivity

    Tune the threshold, away delay, and smoothing to your environment.

  • 100% local

    No accounts, no cloud, no telemetry. Data stays on your device.

Privacy

Privacy comes first

What SignalLock does NOT do is as important as what it does.

The app never talks to a remote server. That isn't a setting — it's the architecture, and the source is open so you can verify it.

  • No internet connection required
  • No location tracking
  • No personal data collection
  • No telemetry or analytics

v0.1.0

Download

Version 0.1.0 — macOS and Windows are ready. Linux coming soon.

Linux

Soon

BlueZ · soon

Modern Linux distributions.

Linux (coming soon)
View source
What you'll see on first launch

macOS

The DMG is signed with an Apple Developer ID and notarized by Apple, so macOS verifies it and opens it without warnings. The only prompt you may see is the standard "downloaded from the Internet, are you sure you want to open it?" confirmation that appears once for any downloaded app — just click Open.

Windows

The installer is currently unsigned, so Windows SmartScreen may display an "Unknown publisher" warning. On the blue screen, click "More info" and then "Run anyway" — the SignalLock setup wizard opens normally from there. The SHA-256 below confirms the file came from us.

Verify your download

Compare the SHA-256 from your terminal to confirm you downloaded the exact file we published:

macOS · Terminal

shasum -a 256 ~/Downloads/SignalLock.dmg

SHA-25698e9a55aadd21b9b889ebbedb59137daa9034529cccc39249130a9ea5397e34d

Windows · PowerShell

Get-FileHash -Algorithm SHA256 .\Downloads\SignalLock-Setup-x64.exe

SHA-2568d847f421c3d874b83be738f24f21b12b97d0708cde5c18f85aa75da42f34838

FAQ

Frequently asked questions

Short answers. The long ones are in the source code.

Does SignalLock unlock my computer?

No. SignalLock only locks. You always use your OS password or biometric auth to unlock. A deliberate decision to avoid creating an automatic attack surface.

Does it track my location?

No. SignalLock does not use Location Services. It only measures Bluetooth signal strength of nearby devices. No location data is ever collected, stored, or transmitted.

Does it require a phone app?

No. SignalLock is a desktop-only menu bar app.

Can I adjust the distance?

Yes. You can tune the RSSI threshold, the away delay, and the smoothing window. Defaults are deliberately conservative.

Will Bluetooth signal always be accurate?

BLE RSSI is inherently noisy. SignalLock uses a moving average and a grace period so single dropouts won't trigger a lock.

What devices can I track?

Any BLE device that advertises: Apple Watch, AirPods, Galaxy Watch, fitness bands, BLE tags (Tile/Chipolo), and modern Bluetooth accessories. Phones themselves are the least consistent option because iPhones and some Android devices rotate BLE addresses for privacy.