ECE 4760: Final Projects

Touch Piano

Wendian Jiang (wj225)

Hanchen Jin (hj424)

Lin Wang (lw569)

Our project designs a touch piano with 3 octaves (37 keys) by connecting a handmade piano-like touch-sensitive keyboard with a PIC32 microcontroller. The sound is generated by using Karplus-Strong algorithm with debounce function and with a sensitive reaction time of several hundred microseconds.

Lab Demonstration

Key points for this design are implementation of capacitive sensor, sound generation by Karplus-Strong algorithm, keyboard building and other detailed problems including keyboard debounce, sound tones, sound lasting time, etc.

The main touch function of this capacitive sensor is implemented by measuring the capacitance difference between the foil touched or not. When human touch the foil, the capacitance of human body is paralleled with the original capacitance of the touch keyboard (the foil), which reduces the original capacitance. By applying the CTMU function combined with ADC function, we could detect this capacitance variance as the touch signal thus achieves the function of touch keyboard.

Then another key focus is the sound generation by the Karplus-Strong algorithm, which is a plucked string synthesis suited to be implemented on the microcontroller. We also add debounce function for avoiding annoying consecutive sharp sounds by one touch and our design could generate chord up to four tones.

The final job is the design and building the keyboard. The basic thought is using silver Aluminum foil for white keys and copper tap with black tap for black keys. The base is a piece of wood board and other hardware such as PIC32 and muxes are mounted on the back of the keyboard thus the keyboard is compact with an elegant appearance.