Hope that helps Start by learning how to communicate between the android device and PC, which can be achieved via Bluetooth or Wi-Fi Android device itself does not have much environmental sensors, so you might need external device, i.e. microcontrollers with such attached sensors (e.g. temperature, humidity, CO2, etc) which you can achieve by using an Arduino or similar microcontrollers.
Are Real-Time Developer Notifications necessary to be enabled for implementing In-App Purchases in an Android app?
this one helps. I figured it out: I missed in Google's guide that the payload I was expecting was base64 encoded in the "data": "longstringofcharacters" portion I pasted above. Once I realized that, I decoded one from my logs, and found the IAP subscription details I was expecting.
Sending Push Notifications When a Firebase Real Time Database Node is Updated