[原创] MicroPyhton-NodeMcuEsp8266，驱动超声波探测器-蜂鸣器-OLED屏幕

开发板：NodeMcu Esp8266

使用语言 ：Micro Pyhton

使用硬件：HC-SR04超声波探测器，蜂鸣器，OLED屏幕

接线图：如下 Micro Pyhton代码：

请修改代码中的你的WiFi名称和WiFi密码，为你自己的路由设定的；

import network
import utime


def WIFI():
    # 连接WiFi
    wlan = network.WLAN(network.STA_IF)
    # 打开WiFi对象
    wlan.active(True)
    # 设置WiFi链接信息
    wlan.connect('huawei-FTO', 'yigeling')

# 连接无线网络：
WIFI()
#

# main.py -- put your code here!
"""
原理：
（1）用IO口给TRIG触发测距，给最少10us的高电平信呈。
(2)模块自动发送 8 个 40khz 的方波，自动检测Echo是否有信号返回。
(3)Echo有信号返回，通过io输出一个高电平，高电平持续的时间就是超声波从发射到返回的时间。测试距离=(高电平时间*声速(340M/S))/2。
"""
#
import machine
from machine import Pin
import time



#超声波检测器vcc引脚，接开发板上的VIN(不然供电不稳，会导致各种鸟问题)
Trig = Pin(12, Pin.OUT)   #触发超声波模块 发射超声波Trig线接           Node Mcu D6引脚
Echo = Pin(13, Pin.IN)    #接收超声波信号 Echo线接                   Node Mcu D7 引脚

#蜂鸣器设定-通电后，鸣响100毫秒
beeper = Pin(14,Pin.OUT) #蜂鸣器引脚(I/0)口线接                      Node Mcu D5引脚
utime.sleep_ms(100)
beeper.on()

#
from machine import Pin, I2C
i2c = I2C(scl=Pin(5), sda=Pin(4))      #SCL接开发板 D1引脚，SDA接开发板D2引脚 GUN和vcc 接开发板 GUN，和3v3引脚

from ssd1306 import SSD1306_I2C
oled = SSD1306_I2C(128, 64, i2c)

oled.text('China - BeiJing', 0, 30)
oled.show()




while True:
    # 给一个高电平触发信号维持20微秒，然后变成低电平
    Trig.value(1)
    time.sleep_us(20)
    Trig.value(0)
    while (Echo.value() == 0):   #如果没有收到信号，再触发一次，发射超声波
        Trig.value(1)
        time.sleep_us(20)
        Trig.value(0)
    if (Echo.value() == 1):     #如果接收到了信号
        ts = time.ticks_us()    #此时定下高电平的开始时刻
        while (Echo.value() == 1):  #如果还是高电平就不断地运行这段代码，直到高电平结束后跳出循环
            pass
        te = time.ticks_us()   #定下高电平结束时刻
        tc = te - ts      #算出高电平维持时间
        distance = str(int((tc * 0.034) / 2))   #取整型后，得到的数值最多为四位数
        num = int(distance)
        if num < 50:
            #如果超声波测量距离小于50厘米，则进行蜂鸣器报警，时长50毫秒
            print('[警告]Distance:', distance, 'cm 距离过近！')
            oled.fill(0)#清屏，上次的内容
            oled.text(' ON:'+distance+'CM', 30, 30)
            oled.show()
            beeper.off()
            utime.sleep_ms(50)
            beeper.on()
        else:
            print('[安全]Distance:', distance, 'cm')
            oled.fill(0)#清屏，上次的内容
            oled.text('YES:'+distance+'CM', 30, 30)
            oled.show()

oled.invert(True)
oled.invert(False)

文字模块代码：

ssd1306.py

必须使用ssd1306.py 这个文件，作为模块导入到main.py里面

使用使用的时候，需要将ssd1306和main.py这两个文件同时上传开发板里面去：

# MicroPython SSD1306 OLED driver, I2C and SPI interfaces

import time
import framebuf


# register definitions
from micropython import const

SET_CONTRAST        = const(0x81)
SET_ENTIRE_ON       = const(0xa4)
SET_NORM_INV        = const(0xa6)
SET_DISP            = const(0xae)
SET_MEM_ADDR        = const(0x20)
SET_COL_ADDR        = const(0x21)
SET_PAGE_ADDR       = const(0x22)
SET_DISP_START_LINE = const(0x40)
SET_SEG_REMAP       = const(0xa0)
SET_MUX_RATIO       = const(0xa8)
SET_COM_OUT_DIR     = const(0xc0)
SET_DISP_OFFSET     = const(0xd3)
SET_COM_PIN_CFG     = const(0xda)
SET_DISP_CLK_DIV    = const(0xd5)
SET_PRECHARGE       = const(0xd9)
SET_VCOM_DESEL      = const(0xdb)
SET_CHARGE_PUMP     = const(0x8d)


class SSD1306:
    def __init__(self, width, height, external_vcc):
        self.width = width
        self.height = height
        self.external_vcc = external_vcc
        self.pages = self.height // 8
        # Note the subclass must initialize self.framebuf to a framebuffer.
        # This is necessary because the underlying data buffer is different
        # between I2C and SPI implementations (I2C needs an extra byte).
        self.poweron()
        self.init_display()

    def init_display(self):
        for cmd in (
            SET_DISP | 0x00, # off
            # address setting
            SET_MEM_ADDR, 0x00, # horizontal
            # resolution and layout
            SET_DISP_START_LINE | 0x00,
            SET_SEG_REMAP | 0x01, # column addr 127 mapped to SEG0
            SET_MUX_RATIO, self.height - 1,
            SET_COM_OUT_DIR | 0x08, # scan from COM[N] to COM0
            SET_DISP_OFFSET, 0x00,
            SET_COM_PIN_CFG, 0x02 if self.height == 32 else 0x12,
            # timing and driving scheme
            SET_DISP_CLK_DIV, 0x80,
            SET_PRECHARGE, 0x22 if self.external_vcc else 0xf1,
            SET_VCOM_DESEL, 0x30, # 0.83*Vcc
            # display
            SET_CONTRAST, 0xff, # maximum
            SET_ENTIRE_ON, # output follows RAM contents
            SET_NORM_INV, # not inverted
            # charge pump
            SET_CHARGE_PUMP, 0x10 if self.external_vcc else 0x14,
            SET_DISP | 0x01): # on
            self.write_cmd(cmd)
        self.fill(0)
        self.show()

    def poweroff(self):
        self.write_cmd(SET_DISP | 0x00)

    def contrast(self, contrast):
        self.write_cmd(SET_CONTRAST)
        self.write_cmd(contrast)

    def invert(self, invert):
        self.write_cmd(SET_NORM_INV | (invert & 1))

    def show(self):
        x0 = 0
        x1 = self.width - 1
        if self.width == 64:
            # displays with width of 64 pixels are shifted by 32
            x0 += 32
            x1 += 32
        self.write_cmd(SET_COL_ADDR)
        self.write_cmd(x0)
        self.write_cmd(x1)
        self.write_cmd(SET_PAGE_ADDR)
        self.write_cmd(0)
        self.write_cmd(self.pages - 1)
        self.write_framebuf()

    def fill(self, col):
        self.framebuf.fill(col)

    def pixel(self, x, y, col):
        self.framebuf.pixel(x, y, col)

    def scroll(self, dx, dy):
        self.framebuf.scroll(dx, dy)

    def text(self, string, x, y, col=1):
        self.framebuf.text(string, x, y, col)


class SSD1306_I2C(SSD1306):
    def __init__(self, width, height, i2c, addr=0x3c, external_vcc=False):
        self.i2c = i2c
        self.addr = addr
        self.temp = bytearray(2)
        # Add an extra byte to the data buffer to hold an I2C data/command byte
        # to use hardware-compatible I2C transactions.  A memoryview of the
        # buffer is used to mask this byte from the framebuffer operations
        # (without a major memory hit as memoryview doesn't copy to a separate
        # buffer).
        self.buffer = bytearray(((height // 8) * width) + 1)
        self.buffer[0] = 0x40  # Set first byte of data buffer to Co=0, D/C=1
        self.framebuf = framebuf.FrameBuffer1(memoryview(self.buffer)[1:], width, height)
        super().__init__(width, height, external_vcc)

    def write_cmd(self, cmd):
        self.temp[0] = 0x80 # Co=1, D/C#=0
        self.temp[1] = cmd
        self.i2c.writeto(self.addr, self.temp)

    def write_framebuf(self):
        # Blast out the frame buffer using a single I2C transaction to support
        # hardware I2C interfaces.
        self.i2c.writeto(self.addr, self.buffer)

    def poweron(self):
        pass


class SSD1306_SPI(SSD1306):
    def __init__(self, width, height, spi, dc, res, cs, external_vcc=False):
        self.rate = 10 * 1024 * 1024
        dc.init(dc.OUT, value=0)
        res.init(res.OUT, value=0)
        cs.init(cs.OUT, value=1)
        self.spi = spi
        self.dc = dc
        self.res = res
        self.cs = cs
        self.buffer = bytearray((height // 8) * width)
        self.framebuf = framebuf.FrameBuffer1(self.buffer, width, height)
        super().__init__(width, height, external_vcc)

    def write_cmd(self, cmd):
        self.spi.init(baudrate=self.rate, polarity=0, phase=0)
        self.cs.high()
        self.dc.low()
        self.cs.low()
        self.spi.write(bytearray([cmd]))
        self.cs.high()

    def write_framebuf(self):
        self.spi.init(baudrate=self.rate, polarity=0, phase=0)
        self.cs.high()
        self.dc.high()
        self.cs.low()
        self.spi.write(self.buffer)
        self.cs.high()

    def poweron(self):
        self.res.high()
        time.sleep_ms(1)
        self.res.low()
        time.sleep_ms(10)
        self.res.high()

用while等待信号，容易出现死锁问题。micropython提供了 machine.time_pulse_us()函数，可以读取指定引脚上脉冲宽度。

谢谢指导