# Interactive Rhythm Learning System by Combining Tablet Computers and Robots
## 2 Rhyth Teaching System
### Musical Score Editing and Playing Functions  
Understanding musical scores is a challenge for music beginners. Figure 1 shows a drum score consisting of six bars [20]. The first three bars primarily involve the hi-hat, snare drum, and bass drum. The note positions are at the top, middle, and bottom parts of the score. Specifically, the hi-hat should be played in quarter notes in a consistent rhythm, whereas the snare and bass drums join in various beats. The bass drum should be played in a quiver of fast rhythm. In the final three bars, the tenor drum and symbol are introduced, and the rhythm becomes complicated. If a learner wants to play a piece of music as shown in Figure 1, he or she must be able to understand the score in advance. However, this is a difficult task for a beginning learner.  
To relieve the burden on children, a relatively intuitive and user-friendly score interface was designed for the rhythm teaching system. Figure 2 shows a piece of the rhythm edited by the proposed system. The score involves five instruments, and teachers can edit and adapt the melody for various instruments. The score of each instrument comprises continuous vertical grids. Four continuous grids represent a bar, and each bar is played within two seconds. The light blue bar represents a beating point. For each grid, four types of beat points can be edited by tapping the grid on the tablet computer, as shown in Figure 3. The four beat point types are a quarter note (Figure 3a), an eighth note (Figure 3b), two eighth notes (Figure 3c), and no beating point (Figure 3d).  
Figure 1: A drum score.  
When an edited score is played by the rhythm teaching system (Figure 4), a cue line appears on the screen of the tablet computer; the score is then scrolled from top to bottom over time. If the beat points reach the cut line, learners must beat the corresponding instruments in time. For example, in Figure 4, a bass drum is beaten. In addition, teachers can insert background music, which can improve the learner's sense of rhythm when practicing rhythm exercises. After the completion of a score edition, the teaching system enables teachers to save the edited score and load it in the next rhythm exercise. Compared with conventional drum scores, the scores shown on this interface are easier for beginners to read. According to field trials, most children understand the rhythms in the score within a short period. After some practice and with a certain level of skills, most children can play a piece of music completely on their own. In addition, children can more easily create their own drum scores for listening and practicing on their own.  
Figure 3: Four types of beat style: (**a**) a quarter note; (**b**) a quarter note (back beat); (**c**) two eighth notes; and (**d**) no beating point.  
Figure 2: Musical score editing and playing functions.  
By applying musical score editing function, teachers can immediately edit scores of various difficulties (Figure 5) corresponding to students' learning progress and adjust the difficulty according to the practice or test outcome. The drum score content includes both basic and advanced rhythm practices for a single drum, two drums, or multiple percussion instruments. In addition, students could also conveniently edit or create their own scores using this musical score editing function.  
Figure 4: An edited score is played by the rhythm teaching system.  
Figure 5: The edited scores of three different difficulties: (**a**) basic; (**b**) advanced; (**c**) difficult.