Twilight APK

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Are you having trouble falling asleep? Are your kids hyperactive when playing with the tablet before bed time?
Are you using your smart phone or tablet in the late evening? Twilight may be a solution for you!

WARNING: Android O does no allow the app to cover your notifications any more..

Recent research suggests that exposure to blue light before sleep may distort your natural (circadian) rhythm and cause inability to fall asleep.

The cause is the photoreceptor in your eyes, called Melanopsin. This receptor is sensitive to a narrow band of blue light in the 460-480nm range which may suppress Melatonin production - a hormone responsible for your healthy sleep-wake cycles.

In experimental scientific studies it has been shown an average person reading on a tablet or smart phone for a couple of hours before bed time may find their sleep delayed by about an hour.

The Twilight app makes your device screen adapt to the time of the day. It filters the flux of blue light emitted by your phone or tablet after sunset and protects your eyes with a soft and pleasant red filter. The filter intensity is smoothly adjusted to the sun cycle based on your local sunset and sunrise times.

Get more from Twilight
1) Bed reading: Twilight is more pleasant on the eyes for night reading. Especially as it is able to lower the screen backlight far below the ability of the backligt controls on your screen

2) AMOLED screens: We have tested Twilight on an AMOLED screen for 2.5 years without any sign of depletion or over-burning. If properly configured Twilight causes less light emission (by enabling dimming) with more equal light distribution (dark areas of the screen such as the status bar get tinted). This may in fact increase your AMOLED screen life time.

Basics on circadian rhythm and the role of melatonin

- location - to find out your current sunset/surise times
- running apps - to stop Twilight in selected apps
- write settings - to set back-light
- network - access smartlight (Philips HUE) to shield you household light from blue

Automation (Tasker or other)

Related scientific research

Amplitude Reduction and Phase Shifts of Melatonin, Cortisol and Other Circadian Rhythms after a Gradual Advance of Sleep and Light Exposure in Humans Derk-Jan Dijk, & Co 2012

Exposure to Room Light before Bedtime Suppresses Melatonin Onset and Shortens Melatonin Duration in Humans Joshua J. Gooley, Kyle Chamberlain, Kurt A. Smith & Co, 2011

Effect of Light on Human Circadian Physiology Jeanne F. Duffy, Charles A. Czeisler 2009

Efficacy of a single sequence of intermittent bright light pulses for delaying circadian phase in humans Claude Gronfier, Kenneth P. Wright, & Co 2009

Intrinsic period and light intensity determine the phase relationship between melatonin and sleep in humans Kenneth P. Wright, Claude Gronfier & Co 2009

The Impact of Sleep Timing and Bright Light Exposure on Attentional Impairment during Night Work Nayantara Santhi, Daniel Aeschbach & Co 2008

Short-Wavelength Light Sensitivity of Circadian, Pupillary, and Visual Awareness in Humans Lacking an Outer Retina Farhan H. Zaidi & Co, 2007

High sensitivity of the human circadian melatonin rhythm to resetting by short wavelength light. Lockley SW, Brainard GC, Czeisler CA. 2003

Sensitivity of the human circadian pacemaker to nocturnal light: melatonin phase resetting and suppression Jamie M Zeitzer, Derk-Jan Dijk & Co 2000

For a desktop alternative, try RedShift (Linux) or on Windows the app which has no relation to this project whatsoever, whose name cannot be said aloud or whispered as it is a Trademark, lets call it Lord Voldemort of the blue light flux filtering apps.Guessed it? Let us know in the comments.

Twilight APK reviews

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Ankush Garg review Ankush Garg
Its a great app. In my phone it is working properly right from the begining. It had also reduced the stress on my eyes.
Stephen Jackson review Stephen Jackson
Very effective and simple to use... Except,
Even after updated and fixes, the red filter randomly turns itself off for no reason and exposes you to blindingly blue or full spectrum light when you least need it. This would be a 5 star app otherwise.
Yeon Hamner review Yeon Hamner
Works fine
Was worried it wouldn't work after I turn off my phone. I was wrong. Works all the time. Cool app.
Tom Malcolmson review Tom Malcolmson
Intentionally wastes resources unless you upgrade to Pro. There are lots of ways to encourage users to pay but the method this app uses - forcing you to leave it running and wasting resources even when not in use - is silly and wasteful. I know that getting users to pay is difficult, but this is not the solution.
Morgan Estes review Morgan Estes
Loses location and switches off randomly
For some reason, it keeps losing my location and changes it to 00.00/00.00. I can't get it to automatically find my location again, and it won't let me enter negative numbers or decimals so I can't manually enter it, either. It's horribly jarring for this to happen and the screen switch to a bright blue with no warning. I can't recommend this app anymore until this gets fixed.
Taylor J review Taylor J
Felt it was odd at first, but when I paused the app--it was like night and day. The red filter is so much easier on the eyes, especially when it's all dark and I'm in bed browsing my phone!
Phil Lampert review Phil Lampert
Works, Sort of.
Settings and profiles don't seem to be applied and / or persist properly. The application seems to revert to its default settings even after changes have been made to the settings. Pausing or stopping the application doesn't revert the environment back to the device's settings properly, for example, it turns off the auto brightness setting on my devices when running, but fails to restore that setting when paused or stopped.
Phil Campagna review Phil Campagna
Actually helps with sleep
I use this partly to keep the screen from disturbing my wife's sleep when I'm reading in bed ... but the hue actually does allow normal sleepiness to creep in for myself as well. On rare occasions, it quits, and the resulting glare can be annoying, but it doesn't happen often. All in all, this is a worthwhile feature to add to your phone.
Impurplepower75 review Impurplepower75
Not a gimic
This works really well. You don't get screen glare and you know when your tired or need to eat etc. False light stops your body from being able to function properly and this app stops that from happening. I would recommend all parents make sure you install it into your children's devices.
madond36dm review madond36dm
I love the idea of this app. I have flux on my pc and wanted something similar. Unfortunately it isn't implemented very well. The app would close down automatically, and I would be forced to open the app so I can re-adjust the color temperature, and hope it sticks. Never seems to, though.
Alejandro Florentini review Alejandro Florentini
Warning! Despite being a good app, it interferes with other apps. For example: I can not grant super user permissions to some apps while using Mobizen or Airdroid to control the phone from a PC over a network. I click and click in the "Grant" box of SuperSU and nothing happens. This anomaly is corrected when I apply pause to the Twilight app.
Kallie Dobbs review Kallie Dobbs
Needs to increase dimming
At the dimmest setting, the screen on my cellphone still hurts my eyes. It would be great if it could be fixed. Also, it would be nice if the light on the navigation buttons (back, home) could be dimmed as well.
Hussein Horack review Hussein Horack
Incompatible with Psiphon
For some reason when this is running (even paused) Psiphon does not work.
Cal R-T review Cal R-T
Crashy but valuable
I'm amazed filters like these aren't a native Android feature. When it stops and that white glare comes back, you realise how poorly optimised most screens are for nighttime viewing. It's a nice reminder of the app's effectiveness, but I wish it didn't feel the need to prove it to me by crashing every half hour.
Maya Parmele review Maya Parmele
It's cool
This is a great idea for an app because I know that I always am on my phone before bed time so this definitely helps. But the app is a little bit confusing