Day and night clock

NightDream 

... a desk clock that is also suitable for the night. In dock mode this app provides a simple digital clock that automatically adjusts its brightness, During the day the display is bright, but in the night it dims to a minimum brightness. Simply adjust the font size using a two-finger-zoom gesture.

Daydream
This app can be used as a Daydream from Android 4.2 on.

Quick alarms
Using a swipe from the left, you can set the alarm clock. Delete it by tapping on the lower right corner. 

Battery 

While charging your mobile device an estimate time is calculated until the battery is full.

Notifications
You can enable notifications for missed phone calls, GMail, WhatsApp and twitter. On Android 4.3+ go to Settings > Security > Notification access > enable NightDream.

 In earlier versions of Android go to Settings > Accessibility > enable NightDream.

In-App Payments

The current weather conditions can be shown below the time.  This feature purchased within the app

The project is open source. If you want to send a donation you can do this via in-app purchase.

Permissions

android.permission.MODIFY_AUDIO_SETTINGS
This permissions allows to siilence the device during the night mode. 

android.permission.RECORD_AUDIO
During the night mode the screen may be deactivated. It can be switched on again if a certain ambient noise level is reached. Therefore the app continuously records audio. The app does not store audio data.

android.permission.WAKE_LOCK
The app is allowed to wake the device from sleep in order to enable the screen and to keep the screen on. 

android.permission.READ_EXTERNAL_STORAGE
The permission is necessary to read background images from the external storage.

Screen Lock

This app uses the Device Administrator permission. The permission is exclusively used to lock the screen while the app is running. Before uninstalling the app the permission must be revoked.