Close your eyes. Let the light take you somewhere calm.
Lumen is an Android app for light-and-sound relaxation. Your phone's flashlight pulses gently through closed eyes while optional sounds play. Offline and free.
- Free
- Works offline
- No account
- No ads
- 18+ recommended
Three steps to a session
The phone's LED flashlight flickers at a steady, slow-to-moderate rhythm (2 to 15 flashes a second) while your eyes are closed. Many people see shifting colours and patterns behind their eyelids. It's a visual journey for relaxation, not a treatment.
Get comfortable
Sit or lie down somewhere safe, ideally in a dim room. Not while driving or doing anything that needs your attention.
Close your eyes
Hold or prop the phone with the flashlight facing you. Start at arm's length.
Pick a session, press play
Choose a mode. Stop any time with the big STOP button, by shaking the phone or by laying it face-down.
What's inside
As of version 0.7.
Explore
A slow drift of speed and brightness for a changing visual journey.
Relax
A steady, gentle rhythm.
Sleep
A slower rhythm for winding down.
Bilateral
Soft beeps that alternate between your left and right ear, with a guided "Calm place" session (about 10 min, offline voice) or a free mode. For relaxation only. Flicker is off unless you add it.
Custom
Sliders for speed, drift, brightness range, light-on share and session length.
Built-in limits
- Sessions are capped at 15 flashes a second and 20 minutes.
- Lumen measures what your phone's flashlight can do reliably and stays under that speed by default.
- If the phone warms up, it slows and dims.
Easy to stop
- Big STOP button and a STOP button in the notification.
- Shake the phone, or lay it face-down.
- After stopping it reminds you to open your eyes and look around.
Your sound, your way
- Optional built-in tones, or keep playing your own music.
- Works fully offline. No internet permission, no account.
- Session timing logs are saved on your phone only.
Photosensitivity and seizure safety
Lumen uses flashing light. Flashing light, especially in the range of about 3 to 30 flashes a second, can trigger seizures in people with photosensitive epilepsy, even with your eyes closed, and even in people who have never had a seizure before. Please read this before using Lumen.
18+Lumen is recommended for adults 18 and over. Do not let children or teenagers use it.
Do not use Lumen if you
- have epilepsy, or a close family member does
- have ever had a seizure, fit or convulsion
- have reacted to flashing or flickering lights, screens or games
- get migraines, especially ones set off by light
- have had unexplained blackouts or fainting
- have had a recent head or brain injury
- are sleep-deprived
- are pregnant
- are in a mental health crisis
If you're not sure, talk to a doctor before using it.
Stop right away if you notice
- twitching or jerking of the face, eyes, arms or legs
- confusion, dizziness or feeling "not yourself"
- changes in your vision, or a sense of lost time
- nausea, headache or anything upsetting
What to do
- Press STOP, or lay the phone face-down.
- Turn away from the light and cover one eye.
- Open your eyes, sit or lie somewhere safe and rest.
- Get medical advice before using Lumen again. If someone has a seizure, call your local emergency number.
Lumen is not a medical device. It doesn't diagnose, treat or prevent any condition. Bilateral mode is for relaxation only: if anything upsetting comes up, or you feel numb or spaced out, stop and open your eyes.
Download
Please read the safety information above before downloading. Lumen isn't on Google Play: you install the APK straight from this page.
Free · Android 8.0+ · Tick the box above to enable the download.
- Version
- 0.7
- Size
- 287 KB (287,366 bytes)
- Released
- 2026-11-02
- Requires
- Android 8.0 or newer
- APK SHA-256
c39e4e8555297b0365029718d884017521866dbb0584a309223a2ccf70e910b9- Signing cert SHA-256
e2e786d56c3279a16cda78fb2107d8ffb161c12820931e6aa6fc6658ff8fe548
Never install a copy whose checksum doesn't match. Same signing key as every Eva's Lab app.
Install in 3 steps
Download the APK
On your Android phone, tick the safety box and tap Download. Check the SHA-256 above if you like.
Allow your browser to install
Android asks to allow "Install unknown apps". This permission belongs to your browser or file manager, not to Lumen. Tap Settings, allow it, then go back.
Tap Install, then switch it off
Tap Install. Afterwards you can turn the permission back off in Settings › Apps › [your browser] › Install unknown apps.
Permissions
- Internet: not requested. Lumen can't go online.
- Foreground service: keeps a session running with the screen off.
- Media playback service: plays the session sounds in the background.
- Notifications: the STOP control in the notification.
- Wake lock: stops the phone sleeping mid-session.
- Flashlight: used for the light. No camera permission is needed.
Changelog
- 0.7 (2026-11-02): First public release. First-run seizure safety warning. Bug report and feature request from inside the app. Layouts for foldable phones.
Lumen questions
Is it safe for me?
Not for everyone. Lumen uses flashing light, which can trigger seizures in some people. Please read the safety section, and if you're unsure, ask a doctor first.
What does it feel like?
Experiences vary. Many people see moving colours and patterns behind closed eyelids during flicker-light sessions. Some see little. It's meant to be a calm, relaxing visual experience, nothing more.
Why do I need to close my eyes?
Lumen is designed for closed eyes: the light reaches you softly through your eyelids, and that's where the patterns appear. Don't look straight into the flashlight with your eyes open.
Can I use it before sleep?
There's a slower Sleep mode for winding down. Don't use Lumen when you're short on sleep, since sleep deprivation raises seizure risk.
Can kids use it?
No. Lumen is recommended for adults 18 and over.
Does it work offline?
Yes, completely. Lumen has no internet permission. The guided voice uses your phone's offline text-to-speech voices.
Where do I get it?
Now. Version 0.7 is the first public release: download it here after reading the safety information. It opens with a first-run safety warning you have to agree to.
☕ Support the lab
Lumen is free. If you'd like to help, buy Eva's Lab a coffee. It pays for building and testing time and keeps the apps free and ad-free.