Do you struggle with falling asleep? Are your children overly energetic after using tablets before bedtime? Are you using smartphones or tablets in the evening, or perhaps you're sensitive to light during migraines? Twilight could be the perfect solution for you!
Recent research indicates that exposure to blue light before sleep can disrupt your natural circadian rhythm, making it difficult to fall asleep. This is due to the photoreceptor in your eyes known as Melanopsin, which is sensitive to blue light in the 460-480nm range. Such exposure can suppress Melatonin production, 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.
The Twilight app adjusts your device's screen to adapt to the time of day, filtering out blue light after sunset and applying a soothing red filter to protect your eyes. The filter's intensity is smoothly adjusted based on your local sunrise and sunset times. Twilight is also compatible with Wear OS devices.
For more detailed information, visit our documentation at http://twilight.urbandroid.org/doc/.
Here are some additional benefits of using 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 show that using Twilight on an AMOLED screen for five years has not caused any depletion or over-burning. When configured correctly, Twilight reduces light emission by enabling dimming and provides a more uniform light distribution, which may even extend the life of your AMOLED screen.
To learn more about circadian rhythms and the role of melatonin, explore 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
Twilight requires the following permissions:
- Location - to determine your local sunset and sunrise times.
- Running apps - to disable Twilight in specific apps.
- Write settings - to adjust the backlight.
- Network - to connect with smart lights like Philips HUE, to shield your household from blue light.
To filter notifications and the lock screen, Twilight may request the activation of the Twilight Accessibility Service. This service is used solely to enhance screen filtering and does not collect any personal information. For more information on privacy, visit https://twilight.urbandroid.org/is-twilights-accessibility-service-a-thread-to-my-privacy/.
Twilight also synchronizes with your Wear OS device, allowing you to control the filtering through a "Wear OS Tile."
For automation features, such as integration with Tasker or other services, check out https://sites.google.com/site/twilight4android/automation.
For those interested in the scientific backing of Twilight, here are some related studies:
- 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, et al., 2012
- Exposure to Room Light before Bedtime Suppresses Melatonin Onset and Shortens Melatonin Duration in Humans - Joshua J. Gooley, et al., 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, et al., 2009
- Intrinsic period and light intensity determine the phase relationship between melatonin and sleep in humans - Kenneth P. Wright, et al., 2009
- The Impact of Sleep Timing and Bright Light Exposure on Attentional Impairment during Night Work - Nayantara Santhi, et al., 2008
- Short-Wavelength Light Sensitivity of Circadian, Pupillary, and Visual Awareness in Humans Lacking an Outer Retina - Farhan H. Zaidi, et al., 2007
