Twilight: Blue light filter

Are you struggling to fall asleep at night? Do your kids seem overly active after playing with their tablets before bedtime? If you're using your smartphone or tablet in the evening or are 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 is due to a photoreceptor in your eyes called Melanopsin, which is sensitive to blue light in the 460-480nm range. Exposure to this light 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 adapt your device's screen to the time of day. It filters out the blue light emitted by your phone or tablet after sunset, replacing it with a soft, pleasant red filter. The intensity of this filter adjusts smoothly according to your local sunset and sunrise times, ensuring your eyes are protected and your sleep cycle remains undisturbed. You can also use Twilight on your Wear OS device for a seamless experience across all your gadgets.

For more detailed information, check out the documentation at http://twilight.urbandroid.org/doc/.

Get More from Twilight:

1. Bed Reading: Twilight offers a more comfortable reading experience at night. It can lower the screen backlight far below the capabilities of standard backlight controls, making it easier on your eyes.

2. AMOLED Screens: Extensive testing on AMOLED screens over five years has shown no signs of depletion or over-burning. When properly configured, Twilight reduces light emission and promotes a more even light distribution, which could potentially extend the life of your AMOLED screen.

Basics on Circadian Rhythm and the Role of Melatonin:

For a deeper understanding, visit these resources:

• http://en.wikipedia.org/wiki/Melatonin
• http://en.wikipedia.org/wiki/Melanopsin
• http://en.wikipedia.org/wiki/Circadian_rhythms
• http://en.wikipedia.org/wiki/Circadian_rhythm_disorder

Permissions:

Twilight requires the following permissions to function effectively:

• Location: To determine your current sunset and sunrise times.
• Running Apps: To pause Twilight in selected applications.
• Write Settings: To adjust the backlight.
• Network: To access smart lighting systems like Philips HUE, helping to shield your household from blue light.

Accessibility Service:

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

Wear OS:

Twilight syncs your Wear OS screen with your phone's filter settings, and you can manage this feature through a "Wear OS Tile."

Automation (Tasker or Other):

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

Related Scientific Research:

Explore these studies to understand the impact of light on sleep:

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