BLEUnlock

BLEUnlock is a small menu bar utility that locks and unlocks your Mac by proximity of your iPhone, Apple Watch, or any other Bluetooth Low Energy device.

This document is also available in Japanese (日本語版はこちら).

Features

No iPhone app is required
Works with any BLE devices that periodically transmits signal from static MAC address
Unlocks your Mac for you when the BLE device is near your Mac, without entering password
Locks your Mac when the BLE device is away from your Mac
Optionally runs your own script upon lock/unlock
Optionally wakes from display sleep
Optionally pauses and unpauses music/video playback when you're away and back
Password is securely stored in Keychain

Requirements

A Mac with Bluetooth Low Energy support
macOS 10.13 (High Sierra) or later
iPhone 5s or newer, Apple Watch (all), or another BLE device that has static MAC address and transmits signal periodically

Installation

Using Homebrew Cask

$ brew install bleunlock

Manual installation

Download the zip file from Releases, unzip and move to the Applications folder.

Setting up

On the first launch, it asks for the following permissions, which you must grant:

Permission	Description
Bluetooth	Obviously, Bluetooth access is required. Choose OK.
Accessibility	This is required to unlock the locked screen. Click Open System Preferences, click the lock icon on the bottom left to unlock, and turn on BLEUnlock.
Keychain	(Not always asked) If asked, you have to choose Always Allow because it is required while the screen is locked.
Notification	(Optional) BLEUnlock shows a message on the lock screen when it locks the screen. It is helpful to know if it's working properly. Additionally, to see the message on the lock screen, you need to set Show previews to always in the Notification preference pane.

NOTE: The number of permissions required increases with each version of macOS, so if you are using an older OS, you may not be asked for one or more permissions.

Then it asks your login password to unlock the lock screen. It will be stored safely in Keychain.

Finally, from the menu bar icon, select Device. It starts scanning nearby BLE devices. Select your device, and you're done!

Options

Option	Description
Lock Screen Now	It locks the screen regardless of whether the BLE device is nearby or not; it will unlock once the BLE device moves away and then moves closer again. This is useful to ensure that the screen is locked before you leave your seat.
Unlock RSSI	Bluetooth signal strength to unlock. Larger value indicates that the BLE device needs to be closer to the Mac to unlock. Choose Disable to disable unlocking.
Lock RSSI	Bluetooth signal strength to lock. Smaller value indicates that the BLE device needs to be farther away from the Mac to lock. Choose Disable to disable locking.
Delay to Lock	Duration of time before it locks the Mac when it detects that the BLE device is away. If the BLE device comes closer within that time, no lock will occur.
No-Signal Timeout	Time between last signal reception and locking. If you experience frequent "Signal is lost" locking, increase this value.
Wake on Proximity	Wakes up the display from sleep when the BLE device approaches while locking.
Pause "Now Playing" while Locked	On lock/unlock, BLEUnlock pauses/unpauses playback of music or video (including Apple Music, QuickTime Player and Spotify) that is controlled by Now Playing widget or the ⏯ key on the keyboard.
Use Screensaver to Lock	If this option is set, BLEUnlock launches screensaver instead of locking. For this option to work properly, you need to set Require password immediately* after sleep or screen saver begins* option in Security & Privacy preference pane.
Set Password...	If you changed your login password, use this.
Passive Mode	By default it actively tries to connect to the BLE device and read the RSSI. Most of the time, the default is recommended and works stably. However, if you are using other Bluetooth things like keyboard, mouse, track pad or most notably Bluetooth Personal Hotspot, the default mode may interfere with each other. 2.4GHz WiFi may interfere as well. If you are experiencing instability of Bluetooth, turn on Passive Mode.
Launch at Login	Launches BLEUnlock when you login.
Set Minimum RSSI	Devices with RSSI below this value will not be displayed in the device scan list.

Troubleshooting

Can't find my device in the list

If your BLE device is not from Apple, BLEUnlock may not able to find the device name. If that is the case, your device is displayed as a UUID (long hexadecimal numbers and hyphens). To identify the device, try moving the device closer to or farther away from the Mac and see if the RSSI (dB value) changes accordingly.

If you don't see any device in the list, try resetting the Bluetooth module as described below.

It fails to unlock

Make sure BLEUnlock is turned on in System Preferences > Security & Privacy > Privacy > Accessibility. If it is already on, try turning it off and on again.

If it asks for permission to access its own password in Keychain, you must choose Always Allow, because it is needed while the screen is locked.

"Signal is lost" occurs frequently

Increase No-Signal Timeout. Or try Passive Mode.

My Bluetooth keyboard, mouse, Personal Hotspot, or whatever Bluetooth, went nuts!

Firstly, Shift + Option + Click the Bluetooth icon in the menubar or Control Center, then click Reset the Bluetooth module.

If the problem persists, turn on Passive Mode.

Notes on MAC address

Unlike classic Bluetooth, Bluetooth Low Energy devices can use private MAC address. That private address can be random, and can be changed from time to time.

Recent smart devices, both iOS and Android, tend to use private addresses that change every 15 minutes or so. This is probably to prevent tracking.

On the other hand, in order for BLEUnlock to track your device, its MAC address must be static.

Fortunately, on Apple devices, if you are signed in with the same Apple ID as your Mac, the MAC address is resolved to the true (public) address.

For other devices, including Android, the way to resolve the address is unknown. If your non-Apple device changes its MAC address over time, unfortunately BLEUnlock can't support it.

To check if the MAC address is resolved correctly, compare the MAC address displayed in the Device scan list of BLEUnlock with the one that is displayed on your device.

Run script on lock/unlock

On locking and unlocking, BLEUnlock runs a script located here:

~/Library/Application Scripts/jp.sone.BLEUnlock/event

An argument is passed depending on the type of event:

Event	Argument
Locked by BLEUnlock because of low RSSI	`away`
Locked by BLEUnlock because of no signal	`lost`
Unlocked by BLEUnlock	`unlocked`
Unlocked manually	`intruded`

NOTE: for intruded event works properly, you have to set Require password immediately after sleep in Security & Privacy preference pane.

Example

Here is an example script which sends a LINE Notify message, with a photo of the person in front of the Mac when it is unlocked manually.

#!/bin/bash

set -eo pipefail

LINE_TOKEN=xxxxx

notify() {
    local message=$1
    local image=$2
    if [ "$image" ]; then
        img_arg="-F imageFile=@$image"
    else
        img_arg=""
    fi
    curl -X POST -H "Authorization: Bearer $LINE_TOKEN" -F "message=$message" \
        $img_arg https://notify-api.line.me/api/notify
}

capture() {
    open -Wa SnapshotUnlocker
    ls -t /tmp/unlock-*.jpg | head -1
}

case $1 in
    away)
        notify "$(hostname -s) is locked by BLEUnlock because iPhone is away."
        ;;
    lost)
        notify "$(hostname -s) is locked by BLEUnlock because signal is lost."
        ;;
    unlocked)
        #notify "$(hostname -s) is unlocked by BLEUnlock."
        ;;
    intruded)
        notify "$(hostname -s) is manually unlocked." $(capture)
        ;;
esac

SnapshotUnlocker is an .app created with Script Editor with this script:

do shell script "/usr/local/bin/ffmpeg -f avfoundation -r 30 -i 0 -frames:v 1 -y /tmp/unlock-$(date +%Y%m%d_%H%M%S).jpg"

This app is required because BLEUnlock does not have Camera permission. Giving permission to this app resolves the problem.

Funding

Since version 1.9.0, binary releases are not notarized by Apple. Because of this, you have to right-click and Open to start, and you have to re-authorize Keychain and other permissions.

My company is not developing iOS or Mac app at the moment, so I don't have access to a paid Apple Developer account.

If you like this app, I'd appreciate it if you could make a donation via Buy Me a Coffee so that I can pay for the Apple Developer Program myself!

Credits

peiit: Chinese translation
wenmin-wu: Minimum RSSI and moving average
stephengroat: CI
joeyhoer: Homebrew Cask
Skyearn: Big Sur style icon

Icons are based on SVGs downloaded from materialdesignicons.com. They are originally designed by Google LLC and licensed under Apache License version 2.0.

License

MIT

dancingpeanut/BLEUnlock