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18.Digital Piano

Project Introduction

The UNIHIKER is equipped with a buzzer that can emit different tones by setting different frequencies. This feature allows for the creation of an electronic piano. In this project, a simple user interface is created where users can play different notes by pressing buttons on the screen. Below is an example of an electronic piano.

18.1.gif

Hardware Required

Code

In this example, UNIHIKER is initialized with Board().begin().

Then, a GUI object is instantiated, and multiple black and white rectangles (representing different piano keys) are created using the fill_rect() function.

Next, a series of event callback functions are defined, each corresponding to a musical note.

Within the callback functions, the buzzer is controlled to emit a sound of a specific frequency and duration using the buzzer.pitch(frequency, duration) function.

Each musical note is bound to a piano key, and when the key is pressed, the corresponding callback function is executed, and the buzzer plays the respective note.

Additionally, a text box displays the name of the currently playing note, allowing the user to identify which note is being played. This creates a simple user interface for an electronic piano on UNIHIKER. 

#  -*- coding: UTF-8 -*-

# MindPlus
# Python
from pinpong.extension.unihiker import *
from pinpong.board import Board,Pin
from unihiker import GUI
import time

# Event callback function
def button_click1():
    buzzer.pitch(262,1)
    text.config(text="C4")
def button_click2():
    buzzer.pitch(294,1)
    text.config(text="D4")
def button_click3():
    buzzer.pitch(330,1)
    text.config(text="E4")
def button_click4():
    buzzer.pitch(349,1)
    text.config(text="F4")
def button_click5():
    buzzer.pitch(392,1)
    text.config(text="G4")
def button_click6():
    buzzer.pitch(440,1)
    text.config(text="A4")
def button_click7():
    buzzer.pitch(494,1)
    text.config(text="B4")
def button_click8():
    buzzer.pitch(277,1)
    text.config(text="C#4")
def button_click9():
    buzzer.pitch(311,1)
    text.config(text="D#4")
def button_click10():
    buzzer.pitch(370,1)
    text.config(text="F#4")
def button_click11():
    buzzer.pitch(415,1)
    text.config(text="G#4")
def button_click12():
    buzzer.pitch(466,1)
    text.config(text="A#4")


u_gui=GUI()
Board().begin()

bg=u_gui.fill_rect(x=0,y=0,w=240,h=320,color="#CCCCFF")
text = u_gui.draw_text(x=185,y=160,text="Musical Scale",origin="center",font_size=30,angle=270)
do=u_gui.fill_rect(x=0,y=3,w=130,h=43,color="#FFFFFF",onclick=button_click1)
re=u_gui.fill_rect(x=0,y=48,w=130,h=43,color="#FFFFFF",onclick=button_click2)
mi=u_gui.fill_rect(x=0,y=93,w=130,h=43,color="#FFFFFF",onclick=button_click3)
fa=u_gui.fill_rect(x=0,y=138,w=130,h=43,color="#FFFFFF",onclick=button_click4)
so=u_gui.fill_rect(x=0,y=183,w=130,h=43,color="#FFFFFF",onclick=button_click5)
la=u_gui.fill_rect(x=0,y=228,w=130,h=43,color="#FFFFFF",onclick=button_click6)
xi=u_gui.fill_rect(x=0,y=273,w=130,h=43,color="#FFFFFF",onclick=button_click7)
bian1=u_gui.fill_rect(x=50,y=32,w=80,h=30,color="#000000",onclick=button_click8)
bian2=u_gui.fill_rect(x=50,y=77,w=80,h=30,color="#000000",onclick=button_click9)
bian3=u_gui.fill_rect(x=50,y=167,w=80,h=30,color="#000000",onclick=button_click10)
bian4=u_gui.fill_rect(x=50,y=212,w=80,h=30,color="#000000",onclick=button_click11)
bian5=u_gui.fill_rect(x=50,y=257,w=80,h=30,color="#000000",onclick=button_click12)


while True:
    time.sleep(1)

Demo Effect

18.2.gif

Extend

Here is a more detailed explanation of the different uses of the buzzer.

Playing Pre-set Melodies

The onboard buzzer of the UNIHIKER board can play a range of pre-set melodies. For example: 

buzzer.play(buzzer.DADADADUM, buzzer.Once) # Play the "DADADADUM" melody once
This line of code will make the buzzer play a melody named "DADADADUM." The buzzer.Once indicates that this melody will be played only once.

  • Other Melodies: DADADADUM, ENTERTAINER, PRELUDE, ODE, NYAN, RINGTONE, FUNK, BLUES, BIRTHDAY, WEDDING, FUNERAL, PUNCHLINE, BADDY, CHASE, BA_DING, WAWAWAWAA, JUMP_UP, JUMP_DOWN, POWER_UP, POWER_DOWN.
  • Play Modes: Once (play once), Forever (play continuously), OnceInBackground (play once in the background), ForeverInBackground (play continuously in the background).

Setting the Tempo

You can set the buzzer's tempo, including the number of notes per beat and the number of beats per minute: 

buzzer.set_tempo(4, 60) # Set the number of notes per beat to 4, and the number of beats per minute to 60
This sets a standard 4/4 time signature with 60 beats per minute.

Playing a Note in the Background

The buzzer can also play notes in the background, allowing other tasks to be performed simultaneously while the note is playing: 

buzzer.pitch(494) # Play a note at 494Hz frequency in the background
This line of code will play a note at 494Hz in the background until it is stopped.

Stopping Playback

Whether playing in the foreground or background, playback can be stopped at any time: 

buzzer.stop() # Stop playback

Redirecting Pins

If needed, the buzzer's output can be redirected to other PWM (Pulse Width Modulation) compatible pins: 

buzzer.redirect(Pin.P0) # Redirect the buzzer output to pin P0
This line of code redirects the buzzer's signal output from the default pin to pin P0.