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!

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.

App Information Twilight

  • App Name
  • Package Name
  • Updated
  • File Size
    4.05 M
  • Requires Android
    2.3 (Gingerbread, API 9)
  • Version
  • Developer
  • Installs
    1,000,000 - 5,000,000
  • Price
  • Category
  • Developer
  • Google Play Link

Twilight Version History

Select Twilight Version :
  • 6.7 (184)
  • 6.7 (181)
  • 6.8 (179)
  • 6.6 (177)
  • 6.6 (175)
  • 6.5 (171)
  • 6.3 (163)
  • 5.9 (149)
  • 5.7 (144)
  • 5.1 (118)
  • Twilight 6.7 (184) APK File

    Publish Date: 2016-10-14
    Requires Android: 2.3 (Gingerbread, API 9)
    File Size: 4 MB (APK file)
    File APK Md5: af014d16952942a73e3e987749a47db8
    File APK Sha1: a39d4b87e0440fdf09ae63c11989f354c3cb853b
    APK Signature: 00a0e53c9a3f5d14da5e698ff420e4a7776ea4b1
    What's new :
    - lower battery use when using "Hide notification when not filtering"
    - several Philips HUE fixes - gradual light changes etc..
    - fix in STOP and PAUSE for scheduled profiles
    - fix for pause state after reboot
  • Twilight 6.7 (181) APK File

    Publish Date: 2016-09-29
    Requires Android: 2.3 (Gingerbread, API 9)
    File Size: 4 MB (APK file)
    File APK Md5: f5d3de8db40db91a3df91eaeda329178
    File APK Sha1: 1d3903cb18bcca7f9e63425e8fd90ba131b6e504
    APK Signature: 00a0e53c9a3f5d14da5e698ff420e4a7776ea4b1
    What's new :
    - faster ambient screen switching
    - workaround for Samsung alarm bug which may crash the app
    - Ambient screen handling: default on Wear and configurable for the phone too
    - redesign (many thanks to Florian Schulte)
    - few fixes, new languages..Always/auto indicator has been switches for hopefully less confusion..
    - Blue light warning can be skipped
    - Fix for profile scheduling - was one day off
    - New explanatory tutorial, warnings for firmwares with issues: Huawei, Meizu, Miui
  • Twilight 6.8 (179) APK File

    Publish Date: 2016-09-29
    Requires Android: 2.3 (Gingerbread, API 9)
    File Size: 4 MB (APK file)
    File APK Md5: fb508de79a346c91c09f33a44379c6b2
    File APK Sha1: a42424dec8188e4cf831806313a9162f3192b6c1
    APK Signature: 00a0e53c9a3f5d14da5e698ff420e4a7776ea4b1
    What's new :
    - lower battery use when using "Stop service outside filter times"
  • Twilight 6.6 (177) APK File

    Publish Date: 2016-07-18
    Requires Android: 2.3 (Gingerbread, API 9)
    File Size: 5 MB (APK file)
    File APK Md5: 6ac1df8f282103cedc2f9f44bce42fbf
    File APK Sha1: 6359f1f9653c4ec12dba64bc7d43f5f9ba612780
    APK Signature: 00a0e53c9a3f5d14da5e698ff420e4a7776ea4b1
  • Twilight 6.6 (175) APK File

    Publish Date: 2016-06-23
    Requires Android: 2.3 (Gingerbread, API 9)
    File Size: 5 MB (APK file)
    File APK Md5: a645a84bffd7283ab5d406c21abe98e4
    File APK Sha1: 2f216b84cff13db10094047d22e4c6de376fa5ef
    APK Signature: 00a0e53c9a3f5d14da5e698ff420e4a7776ea4b1
  • Twilight 6.5 (171) APK File

    Publish Date: 2016-06-11
    Requires Android: 2.3 (Gingerbread, API 9)
    File Size: 5 MB (APK file)
    File APK Md5: af73f28568ef03d608868fd7404ad4da
    File APK Sha1: dacbac332785f1e1fad22655919f41d58dfa66ae
    APK Signature: 00a0e53c9a3f5d14da5e698ff420e4a7776ea4b1
  • Twilight 6.3 (163) APK File

    Publish Date: 2016-07-03
    Requires Android: 2.3 (Gingerbread, API 9)
    File Size: 5 MB (APK file)
    File APK Md5: 5036d55f3181ea888381ef9bf8a71306
    File APK Sha1: 73e44cc9344da130b6c2edfb6668f92a2813f44c
    APK Signature: 00a0e53c9a3f5d14da5e698ff420e4a7776ea4b1
  • Twilight 5.9 (149) APK File

    Publish Date: 2016-02-22
    Requires Android: 2.3 (Gingerbread, API 9)
    File Size: 5 MB (APK file)
    File APK Md5: 3c9b059793f2bb66c9eb2dbf6e7c6c66
    File APK Sha1: bfc4b266805f9d280a5c61e2e5e2924a3ae6a6ad
    APK Signature: 00a0e53c9a3f5d14da5e698ff420e4a7776ea4b1
  • Twilight 5.7 (144) APK File

    Publish Date: 2016-02-18
    Requires Android: 2.3 (Gingerbread, API 9)
    File Size: 5 MB (APK file)
    File APK Md5: 3aebe84ef23cc4a4de9379834caff03d
    File APK Sha1: 5d4f73b8b4bd2acde83fae4aac8b0609be4f0003
    APK Signature: 00a0e53c9a3f5d14da5e698ff420e4a7776ea4b1
  • Twilight 5.1 (118) APK File

    Publish Date: 2015-12-10
    Requires Android: Android 2.2+
    File Size: 2 MB (APK file)
    File APK Md5: b6e872513f7a390a157ee099b5b2cbf7
    File APK Sha1: f4d2799a2dc47e6f603f680c9cf82570bb1613a4
    APK Signature: 00a0e53c9a3f5d14da5e698ff420e4a7776ea4b1
    What's new :
    5.1 - fix for unscheduling profile change when all schedules are deleted 5.0 - fix for Android 6.0: switching between users, turn of notification - fix for auto-brightness on device without sensor 4.9 - fix for Android 6.0 and landscape 4.8 - set times when profiles switch (experimental) - ability to set higher color temperatures for the day 4.7 - Tasker plug-in - Fix for entering location manually - Android M compatibility

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