The secret of "singing" on the music ladder is that an inductor circuit (3.3 volts DC, no potential safety hazard) is installed under the ladder. As long as pedestrians pass by, they lightly step on the ladder, rely on vibration induction, and then use independent cables to transmit data, and then the computer decodes and synthesizes audio and sends it to the audio amplifier system, and the music sounds. Moreover, the whole step is arranged according to the piano keyboard, and the timbre is also very close to the piano. If you can play the piano, you can really walk out a section of Ode to Joy or other music you like. Even if you don't know how to play the piano, if you are interested, try stepping on different steps a few times, and you can find out "Dolemi".