

THIS APP HAS PRE-OREO FUNCTIONALITY AND IS THEREFORE NOT AVAILABLE IN GOOGLE PLAY STORE.
The app can be downloaded here
(manual installation using a file manager).
Version 1.0 (January 2021) for Android 6.0+
Purpose
ReAlert is a small utility that runs in the background to detect, show and repeat new notifications in various ways. When the notification is cleared, ReAlert will stop.Description
Newer smartphones are often lacking a notification LED. And if they do have one, the newer Android operating system limits its functionality. Color and blink rate are not selectable.Without LED, a notification is only perceptable by turning on the screen, or a speciak warning app must have been installed. Various apps will do this. each in its own way.
ReAlert combines many - if not all - available methods in a single small and battery-friendly app.
1. Pre-Oreo LED functionality (color, on/off-time)
2. Continuous on-screen notification using icons (like NoLED)
3. 'Ping'-notification for Moto/Ambient displays
4. Screen on/off pulses
5. Flash, sound, vibration
Ad 1: Starting with Android Oreo ('channels') manually selecting the LED color is no longer possible, and for an app it's rather laborious. Because ReAlert is compiled for Android 6, it can change color and blink rate by sending a dummy notification.
Ad 2: ReAlert can turn on the screen and show the icon of the app that generated the notification. The icon moves every minute to prevent screen burning. This is a good option with AMOLED displays, as they have lower battery consumption.
Ad 3: A Moto of Ambient display can be triggered by a short-living dummy notification. If the interval isn't too short, this may be the best (battery-friendly) option.
Ad 4: The screen is turned on for one second. This consumes much more battery then option 3.
Ad 5: The camera flash is turned on for 100 ms. Sound and vibration are the only non-visual options.
Options 2-3-4 won't go well together, but apart from that, any combination can be used.
When a screen lock is detected. option 2 (Continuous on-screen icon) will terminate right after starting. Option 2 (Screen pulse) will then be faster, consuming less battery.
ReAlert will run on Android version 6.0 or later, on smartphone and tablet, and will ask the following permissions:
BIND_NOTIFICATION_LISTENER_SERVICE: to detect notifications
IGNORE_BATTERY_OPTIMIZATIONS: to run in the background
WRITE_EXTERNAL_STORAGE: to play installed notification sounds
ACCESSIBILITY_SERVICE: to start an activity
READ_PHONE_STATE: to detect missed calls
WRITE_SETTINGS: to adjust screen brightness
Usage
After installation and accepting the necessary permissions, 'Accessibilty' may have to be manually enabled under (device) Settings / Accessibility.There are five app categories for handling notifications:
'Calendar': | choose an app withh 'Select Calendar app' (any app may be selected) |
'Phone': | as Calendar, using 'Select Phone app' |
'SMS': | as Calendar, using 'Select SMS app' |
'Mail': | as Calendar, using 'Select Mail app' |
'Other': | all other c.q. selected apps |
Each category has a submenu, of which the most important settings are shown in the 'Settings' overview.
As an example the 'SettingsPhone' submenu is shown, of which most parts will be briefly explained:


The screen is kept on continuously, showing (on a black background) the icon of the app that generated the notification. With an AMOLED display the battery consumption will be relativly low. (This is the method used by the 'NoLED' app.)
Screen pulse
The screen is turned on for one second. With short intervals this will consume more battery.
Ping
A short-living dummy notification triggers the Moto/Ambient display.
Priority
Standard the most recent notification is handled. A category is not overruled by another category unless that has equal or higher priority.
DND mode
ReAlert can handle 'Do Not Disturb' in two ways: 'Silent' continues as usual, but without sound and vibration, 'Suspend' will suspend all actions until DND ends.
LED
Color and On/Off times are chosen from a list (like most settings). With On/Off = 'off', no dummy notification is gegerated.
Interval
Each category has its own 'per app' interval. Using the (blue) seekbar in the main screen, a general interval is set to have a higher Flash/Ping/Pulse rate.
Limit (screen)/(all)
Defines the number of hours after which ReAlert will stop all (screen related) activities.
Sound
Any installed notification sound can be chosen.
Bluetooth LED module
A DIY external RGB LED with its own supply. ReAlert will send on/off codes. (Schematics available on request.)
All categories have these settings. The 'Other' category adds a setting 'Selected apps only'. When unchecked, notifications are handled of any app not falling in the other categories. When checked, one or more user applications can be selected. They will be handled with the same 'Other' settings.
IMPORTANT |
Under Android 10+ notifications may get seriously delayed by 'Adaptive Notifications'. This setting is enabled by default and affects 'Ping' in particular. |
The working of orientation and proximity sensors is device dependent. Samsung an Xiaomi, for instance, have a capacative type proximity sensor that will detect your ear, but not fabrics or most other materials. For a first reading, the orientation sensor usually needs a minimal movement after getting activated. To save battery, both sensors are activated only during 'Icon screen' and 'Screen pulse'.

Disclaimer
The ReAlert app is free for private use. Bryk will accept no liability for any damage resulting from its usage.Privacy statement
ReAlert will only ask permissions that are necessary for fulfilling the task indicated in its description.No data is collected other than necessary for fulfilling this task, and no data is in any way transmitted from/to your device or from/to another application.
© Bryk 2020-2022
Egbert Boerma
See also: Mailflag, email IMAP IDLE notification service with advanced filtering