聲音感測器

學會使用MCP3008類比轉數位的概念ADC(Analog Digital Convert)後，其實有很多零組件都可以上手使用，比如聲音感測器、瓦斯偵測器等，這次介紹Sound聲音偵測器，就可以把它應用在家電控制上。

# 檢視類比輸出值方便調整
from gpiozero import MCP3008, Button
import time

sound = MCP3008(0)
loop = 1
running = True
digital_sound = Button(21)

while running:
    try:
        print('{}-目前聲音值：{:.4f}, Button值：{}'.format(loop, sound.value, digital_sound.value))
        time.sleep(0.1)
        loop += 1
    except KeyboardInterrupt:
        running = False

# 拍手控制LED的亮暗
import RPi.GPIO as GPIO
from gpiozero import LED
from signal import pause

#GPIO SETUP
sound = 21
led = LED(17)
GPIO.setmode(GPIO.BCM)
GPIO.setup(sound, GPIO.IN)


def callback(channel):
    if led.value:
        led.off()
    else:
        led.on()


GPIO.add_event_detect(sound, GPIO.BOTH, callback=callback, bouncetime=300)  # let us know when the pin goes HIGH or LOW

pause()

# 通用型類比動態繪圖程式
from gpiozero import MCP3008
import time
import matplotlib.pyplot as plt
import matplotlib.animation as animation


adc = MCP3008(0)

# 圖形起始變數設定
fig, ax = plt.subplots()
line, = ax.plot([], [], lw=2)
ax.grid()
xdata, ydata = [], []


# 心跳資料值迭代產生器
def data_gen(t=0):
    cnt = 0
    while cnt < 1000:
        cnt += 1
        t += 0.1
        yield t, adc.value * 1023


# 圖形啟始函數
def init():
    # gpiozero ADC傳回0與1之間的轉換數值
    # ax.set_ylim(0.4, 0.8)
    # 設定Y軸高度，若使用傳回值為10位元的函數，可以改用1023為高度值
    ax.set_ylim(0, 1023)
    ax.set_xlim(0, 10)
    del xdata[:]
    del ydata[:]
    line.set_data(xdata, ydata)
    return line,


# 心跳圖執行繪製
def run(data):
    # 更新資料
    t, y = data
    xdata.append(t)
    ydata.append(y)
    xmin, xmax = ax.get_xlim()

    if t >= xmax:
        ax.set_xlim(xmin, 2*xmax)
        ax.figure.canvas.draw()
    line.set_data(xdata, ydata)

    return line,


ani = animation.FuncAnimation(fig, run, data_gen, blit=False, interval=10,
                              repeat=False, init_func=init)
plt.show()