Gyroscope ble mcu project

So I want guidance on a project that I’ve been thinking. I want to guidance precisely because I don’t have anything made yet but I have the idea and I want to make sure that if I get started on a prototype that I consider many of the options available or pitfalls that you guys with more experience might already know about.

So I want to make a compact gyroscope that communicates with a smart phone. I guess I would need the gyroscope, the Bluetooth module, the battery and the micro controller. However given that by compact I mean something as small as a box of matches the only controller that comes to mind is the attiny.

would the tiny via good candidate to read gyroscope data and simply communicate the state of alarm or no alarm based on a specific orientation of the gyroscope to the mobile device? I only need to know if the gyroscope his level or not in one dimension and if it is then no alarm is sent to the mobile however if it is not level than an alarm command must be sent to the mobile. This means that blue to come in communication would be very simpl I only need to know if the gyroscope is level or not in one dimension and if it is then no alarm is sent to the mobile however if it is not level than an alarm command must be sent to the mobile. This means that Bluetooth communication would be A very small piece of data which would simply be alarm or no alarm. However communication would have to be periodic at least once every 10 seconds which brings my second worry to mind which is battery consumption versus battery capacity which would need to be inside of a very small form factor to fit inside a box of matches.