Raspberry Pi Pico － 超音波距離センサ

from machine import Pin,ADC,SPI
import utime
import max7219

# GPIO Pinの設定
trig = Pin(20, Pin.OUT)
echo = Pin(21, Pin.IN)
trig.value(0)
# 温度補正用
sensor_temp = machine.ADC(4) # 内蔵温度センサーはADC4
conversion_factor = 3.3 / (65535) # 変換係数

# Dot Matrix LED
spi = SPI(0,sck=Pin(2),mosi=Pin(3))
cs = Pin(5, Pin.OUT)
num_matrix = 4
display = max7219.Matrix8x8(spi, cs, num_matrix)
display.brightness(2)

def measure():
    global temperature,L
    trig.value(1)
    utime.sleep_us(10)
    trig.value(0)
    while echo.value()==0:
        t1=utime.ticks_us()
    while echo.value()==1:
        t2=utime.ticks_us()
    #　エコー時間 (us)
    t=t2-t1
    
    t_read = sensor_temp.read_u16() * conversion_factor
    temperature = 27 - (t_read - 0.706)/0.001721
    # 音速 (m/s)
    Vs = 331.5 + 0.6*temperature
    # 距離
    L = Vs*t/2/1000 

def disp_ledmatrix(string):
    display.fill(0)
    str_length = len(string)
    display.text(string, 8*(4-str_length), 0, 1)
    display.show()

while True:
    measure()
    L_round = int(L)
    disp_string = str(L_round)
    disp_ledmatrix(disp_string)
    print('temp: ', temperature, 'deg, dist: ', L_round)
    utime.sleep(0.5)