We use a Samsung Tab A that we use in ‘network datasource’ mode to raise alarms from Benjamin’s watch using wifi (it connects to the phone in his bedroom that is connected to the pebble watch).
When we first started to use it the ‘power saving’ feature used to shut down the OpenSeizureDetector background process that caused it to fail silently, but Sandie found the option to disable this.
There was a software update yesterday that upgraded it to Android 7.1.1, which broke it again. If the device is running on battery and the screen is switched off, OpenSeizureDetector starts to give fault warning pips after 6-8 minutes. I am pretty sure it is the wifi going to sleep, because as soon as you put the screen on, OpenSeizureDetector changes to OK and the fault pips stop.
The Wifi Advanced settings are set to always on, so it should have been ok, but it turns out there is now a more specific setting….
In Settings–>Apps–>[Three dots]–>Special Access–>Optimise Battery Usage. You can then select “All apps” and OpenSeizureDetector. This prevents OpenSeizureDetector being ‘optimised’ for battery usage (from https://forum.vodafone.co.uk/t5/Android/S8-wifi-disconnects-on-sleep/td-p/2562811).
This ‘optimisation’ is a pain if you want something to just keep running!