Android 8.0 and up · free

Torch Lock

If the Amazon Flex app leaves your flashlight on after scanning, this switches it off. Free, no ads, no account — and it has no internet permission at all, so it cannot send anything anywhere.

Download free · 6.7 MB

Direct APK. Not on Google Play.

The problem

The Amazon Flex app turns on your phone's flashlight to read barcodes in low light. On a lot of Android phones it does not reliably turn it back off — so the torch stays burning after the scan, through the next stop, sometimes for the rest of the block.

That costs you battery on the one device you cannot afford to lose mid-route, it heats the phone enough that some models throttle, and in a dark stairwell it is simply in your way. Toggling it off by hand works until the next scan turns it on again.

This is a bug in someone else's app and it is worth reporting to Amazon. Torch Lock is a workaround so you do not have to wait for them.

What it does

Switches it off

Watches the torch and turns it off the moment anything turns it on — Flex, a stray tap on the quick-settings tile, a pocket press. You see a flicker instead of a light.

Waits out the scanner

While Flex is still holding the camera, no app on Android can take the torch from it — that is enforced by the operating system. Torch Lock shows WAIT and keeps trying, so the torch goes out the instant Flex lets go.

Stays on

Set it once. It survives a reboot and restarts itself if Android stops it for memory. A silent notification sits at the bottom of your shade with a one-tap Stop.

Counts them

Shows how many times it has switched the torch back off, so you can see for yourself how often it is happening.

Battery

Negligible. It sleeps on a system callback and does nothing until the torch changes state. Far less than leaving the flashlight burning.

It cannot track you

Not a promise — a property of how it is built, and you can check it on your own phone in about ten seconds. These are all the permissions it asks for:

Foreground service

Keeps it running when you leave the app.

Notifications

The ongoing notice Android requires for the above.

Run at startup

So it is still working after you restart your phone.

There is no internet permission. Android itself blocks every outbound connection an app without it attempts, so Torch Lock cannot send your data anywhere regardless of what its code says. There is no camera permission either — switching a torch does not need one.

No analytics, no crash reporting, no advertising, no account, no advertising ID. It stores one on/off setting and a counter, in its own private storage. Uninstalling removes them.

Open Settings → Apps → Torch Lock → Permissions after installing and you will see the list above and nothing else.

Installing

It is not on Google Play, so Android will ask whether to allow installing from this source. That prompt appears for any app distributed as an APK. Download, open the file, allow when asked, then open Torch Lock and turn the switch on.

If you want to confirm the file you downloaded is the one published here, its SHA-256 is de40d370ef332c7d55691c9351f919201d11cab6cdc770f4f64f608d4bd62e3b — also at bin/SHA256SUMS.txt.

Download free · 6.7 MB

What it is not

Not a hardware lock. Android gives no way to stop the torch being switched on, only to switch it off afterwards. Expect a brief flicker, not darkness.
Not able to override an app holding the camera. Nothing can. It waits and switches the torch off the second that app releases it.
Not affiliated with Amazon in any way, and it does not connect to the Flex app, read from it, or interfere with it. It only switches off a light.