Are you struggling to fall asleep at night? Do your kids seem overly energetic after using their tablets before bedtime? If you frequently use your smartphone or tablet in the evening, or if you're sensitive to light during migraines, Twilight could be the solution you need!

Recent research indicates that exposure to blue light before sleep can disrupt your natural circadian rhythm, making it harder to fall asleep. This issue stems from a photoreceptor in your eyes known as Melanopsin, which is sensitive to blue light in the 460-480nm range. This sensitivity can suppress the production of Melatonin, a crucial hormone for maintaining healthy sleep-wake cycles. Studies have shown that reading on a tablet or smartphone for a couple of hours before bed can delay sleep by about an hour.

Twilight is an app designed to help by adapting your device's screen to the time of day. It filters out blue light from your phone or tablet after sunset, replacing it with a soothing red filter that protects your eyes. The intensity of the filter adjusts smoothly based on your local sunset and sunrise times, ensuring a seamless transition.

You can also extend Twilight's benefits to your Wear OS device, ensuring consistent protection across all your gadgets.

Documentation

For more detailed information, visit: http://twilight.urbandroid.org/doc/

Get More from Twilight

1. Bed Reading: Twilight enhances the night reading experience by making it more comfortable on the eyes. It can dim the screen beyond the capabilities of standard backlight controls.

2. AMOLED Screens: Our tests on AMOLED screens over five years show no signs of depletion or over-burning. When properly configured, Twilight reduces light emission and provides a more even light distribution, potentially extending your screen's lifespan.

Basics on Circadian Rhythm and the Role of Melatonin

To learn more about these topics, check out these resources:

• Melatonin
• Melanopsin
• Circadian Rhythms
• Circadian Rhythm Disorder

Permissions

Twilight requires the following permissions to function effectively:

• Location: To determine your local sunset and sunrise times.
• Running Apps: To pause Twilight in selected apps.
• Write Settings: To adjust the backlight.
• Network: To connect with smart lights like Philips HUE to shield your household from blue light.

Accessibility Service

To filter notifications and the lock screen, Twilight may request the use of its Accessibility Service. This service is used solely to enhance screen filtering and does not collect any personal data. For more information, visit: https://twilight.urbandroid.org/is-twilights-accessibility-service-a-thread-to-my-privacy/

Wear OS

Twilight syncs with your Wear OS device, allowing you to control filtering through a "Wear OS Tile".

Automation (Tasker or Other)

For automation options, visit: https://sites.google.com/site/twilight4android/automation

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 & Co, 2008
• Short-Wavelength Light Sensitivity of Circadian, Pupillary, and Visual Awareness in Humans Lacking an Outer Retina - Farhan H. Zaidi & Co, 2007