The Player App will run on a Raspberry Pi that will physically be in the same box as the Braille cells and buttons.

It plays scenarios that have been stored in a file in a particular format

One of your main jobs in this phase is to design and document this format

You can access the official Simulator API and implementation here The project contains javadoc as well.

Take a look at this Sample Scenario.

It will give you a pretty good idea of the kind of capabilities the Player app needs to have.

All the interaction in the scenario is stored in the file that the Player app will read

The Player app will use audio to communicate with the visually-impaired user

You will need to support two options

1. Playing audio clips stored as files (either for speech or for sound fx)
2. Using a text to speech library to create audio on the fly. You should research available text to speech libraries online, and select one for your project.