BrickMusicTable: A LEGO brick-based tabletop sequencer

We present the BrickMusicTable, a prototype for a tabletop tangible user interface (TUI) for musical purposes that uses LEGO bricks. Our resulting musical instrument is a sequencer that produces sound based on visually tracked bricks placed on a LEGO ground plate. The current prototype recognises different sizes and colours of bricks and their position on the sequencer as notes. In addition, putting small coloured pins on top of these 'note bricks' enables different sound modulations. Additional brick-controlled 'sliders' allow changing the speed, pitch and volume of the sequencer. The iterative design and development process was accompanied by participating musicians, who gave feedback upon testing the prototype during development. We consider our prototype as a successful case study of novel technology and proof-of-concepts especially using a top-down camera recognition for a tabletop TUI and thus enabling new interaction techniques through stacking bricks on each other on the sequencer. At the same time the design and development process revealed different problems, but also led to possible solutions concerning illumination and a stable image analysis.