探索MicroPython(四)--传感器应用

传感器应用

1. 三轴加速度计MMA7660
2. 温度传感器DS18B20
3. 温湿度传感器DHT11
4. 气压传感器BMP280

1. 三轴加速度计MMA7660

pyBoard中内置了一个三轴加速度计MMA7660，输出x,y,z三个轴的加速度，测量范围大概是-1.5g到1.5g。pyb中关于MMA7660的构造函数和使用方法如下所示：

示例代码为：

import pyb
from machine import Pin,I2C#初始化相关模块
accel = pyb.Accel()#测量结果
x = accel.x()
y = accel.y()
z = accel.z()

2. 温度传感器DS18B20

DS18B20是常用的温度传感器，它是单总线式传感器，连接原理图如下所示：

pyBoard中单总线模块文件是"onewire.py"，DS18B20模块文件是"DS18X20.py",单总线模块的构造函数和使用方法为：

DS18B20的模块的构造函数和使用方法为：

温度传感器代码示例：

#引用相关模块
from pyb import delay
from machine import Pin,I2C
from onewire import OneWire
from ds18x20 import DS18X20#初始化DS18B20
ow= OneWire(Pin('X11')) #使能单总线
ds = DS18X20(ow)        #传感器是DS18B20
rom = ds.scan()         #扫描单总线上的传感器地址，支持多个传感器同时连接while True:ds.convert_temp()   #温度采集转换temp = ds.read_temp(rom[0]) #温度显示,rom[0]为第1个DS18B20

3. 温湿度传感器DHT11

DHT11也是常见的和常用的湿度传感器，其也是单总线传感器。
![在这里插入图片描述](https://img-blog.csdnimg.cn/20200203132102286.png?#pic_center =300x225#pic_center =500x)
pyBoard中dht11.py文件中的构造函数和使用方法为：

DHT11的示例代码为：

#引入相关模块
from pyb import delay
from machine import Pin,I2C
from dht import DHT11#创建DTH11对象dt
dt=DHT11(Pin('X12'))
delay(1000)          #首次启动停顿1秒然传感器稳定while True:dt.measure()         #温湿度采集te=dt.temperature()  #获取温度值dh=dt.humidity()     #获取湿度值

4. 气压传感器BMP280

BMP280是常用的气压传感器，我们需要编写BMP280的驱动文件“bmp280.py”,该模块文件中的构造函数和使用方法为：

BMP280的代码示例为：

import pyb
import bmp280
from machine import Pin,I2C#初始化BMP280，I2C接口2
BMP = bmp280.BMP280(I2C(2))#测量结果
Tem = BMP.getTemp()
Pre = BMP.getPress()
Alt = BMP.getAltitude()

bmp280.py中的代码为：


BMP280_I2C_ADDR = const(0x76)class BMP280():def __init__(self, i2c):self.i2c = i2cself.dig_T1 = self.get2Reg(0x88)self.dig_T2 = self.short(self.get2Reg(0x8A))self.dig_T3 = self.short(self.get2Reg(0x8C))self.dig_P1 = self.get2Reg(0x8E)self.dig_P2 = self.short(self.get2Reg(0x90))self.dig_P3 = self.short(self.get2Reg(0x92))self.dig_P4 = self.short(self.get2Reg(0x94))self.dig_P5 = self.short(self.get2Reg(0x96))self.dig_P6 = self.short(self.get2Reg(0x98))self.dig_P7 = self.short(self.get2Reg(0x9A))self.dig_P8 = self.short(self.get2Reg(0x9C))self.dig_P9 = self.short(self.get2Reg(0x9E))self.mode = 3self.osrs_p = 3self.osrs_t = 1self.setReg(0xF4, 0x2F)self.setReg(0xF5, 0x0C)self.filter = 3self.T = 0self.P = 0self.version = '1.0'def    short(self, dat):if dat > 32767:return dat - 65536else:return dat# set regdef    setReg(self, reg, dat):self.i2c.writeto(BMP280_I2C_ADDR, bytearray([reg, dat]))# get regdef getReg(self, reg):self.i2c.writeto(BMP280_I2C_ADDR, bytearray([reg]))t =   self.i2c.readfrom(BMP280_I2C_ADDR, 1)return t[0]# get two regdef    get2Reg(self, reg):self.i2c.writeto(BMP280_I2C_ADDR, bytearray([reg]))t =  self.i2c.readfrom(BMP280_I2C_ADDR, 2)return t[0] + t[1]*256def get(self):adc_T = (self.getReg(0xFA)<<12) + (self.getReg(0xFB)<<4) + (self.getReg(0xFC)>>4)var1 = (((adc_T>>3)-(self.dig_T1<<1))*self.dig_T2)>>11var2 = (((((adc_T>>4)-self.dig_T1)*((adc_T>>4) - self.dig_T1))>>12)*self.dig_T3)>>14t = var1+var2self.T = ((t * 5 + 128) >> 8)/100var1 = (t>>1) - 64000var2 = (((var1>>2) * (var1>>2)) >> 11 ) * self.dig_P6var2 = var2 + ((var1*self.dig_P5)<<1)var2 = (var2>>2)+(self.dig_P4<<16)var1 = (((self.dig_P3*((var1>>2)*(var1>>2))>>13)>>3) + (((self.dig_P2) * var1)>>1))>>18var1 = ((32768+var1)*self.dig_P1)>>15if var1 == 0:return  # avoid exception caused by division by zeroadc_P = (self.getReg(0xF7)<<12) + (self.getReg(0xF8)<<4) + (self.getReg(0xF9)>>4)p=((1048576-adc_P)-(var2>>12))*3125if p < 0x80000000:p = (p << 1) // var1else:p = (p // var1) * 2var1 = (self.dig_P9 * (((p>>3)*(p>>3))>>13))>>12var2 = (((p>>2)) * self.dig_P8)>>13self.P = p + ((var1 + var2 + self.dig_P7) >> 4)return [self.T, self.P]# get Temperature in Celsiusdef getTemp(self):self.get()return self.T# get Pressure in Padef getPress(self):self.get()return self.P# Calculating absolute altitudedef getAltitude(self):return '%.2f'%(44330*(1-(self.getPress()/101325)**(1/5.256)))# sleep modedef poweroff(self):self.setReg(0xF4, 0)# normal modedef poweron(self):self.setReg(0xF4, 0x2F)