I created a MQTT Alarm Control Panel for use with Home Assistant’s new Manual Alarm Control Panel component. This project was built using a Raspberry Pi 3 and a 7" Touchscreen display running Android Things.
Build instructions: https://www.hackster.io/thanksmister/mqtt-alarm-control-panel-for-home-assistant-a206cc
Demo video: https://www.youtube.com/watch?v=xspCZoRIBNQ
Source code: https://github.com/thanksmister/androidthings-mqtt-alarm-panel
I also created an Android tablet version that is available on Google Play and as a downloadable APK file for sideloading.
Google play store: https://play.google.com/store/apps/details?id=com.thanksmister.iot.mqtt.alarmpanel
Source code and APK file: https://github.com/thanksmister/android-mqtt-alarm-panel