Implementation

An IR Receiver, via GPIO Pin, or Accelerometer, via I2C, will first send a playback event to the MCU. For example, button 2 on the IR remote would play a song, or tilting the MCU right would skip a song. DigiJam will then send the playback event to its AWS Device Shadow via HTTP Post. This shadow update will trigger an AWS Lambda function and forward the playback event to that function. The Lambda function will verify the playback update and then handle requests accordingly with Spotify API (auth, playing, skipping, etc). The Spotify API will execute the playback to an external device and send back necessary information to Lambda. Lambda then updates the device shadow with that new information such as song name and artist. The MCU will make a HTTP Get request to the device shadow to access this new updated information and use it to display on the OLED via SPI. Before it is displayed to the OLED, the song is passed through a resizing algorithm in order to always fit on the OLED.