树莓派4B通过Python读取MLX90614温度

首先科普IIC，即I2C

IIC（Inter-Integrated Circuit）其实是IICBus简称，所以中文应该叫集成电路总线。

包括两个SDA和SCL，SDA是串行数据线，SCL是串行时钟线，IIC工作方式为半双工。

可以看到MLX90614有四个引脚，vcc接3.3v，GND接地，SDA和SCL分别对应树莓派相应接口（见下图）。

接好线之后

首先安装IIC库（这个一般树莓派操作系统自带）

sudo apt install i2c-tools

再装专门为python的smbus

sudo apt install python-smbus

安完上面两个，就可以打开IIC

sudo raspi-config

选择5 interface options，然后选择P5 I2C，打开这一项

之后就可以查看模块的地址了（下面代码如果运行不了，自己加管理员权限sudo）

i2cdetect -y -a 1

如果树莓派SDA和SCL接的是SDA.1和SCL.1，那么模块地址就是0*5a，如图

这样就说明检测到了模块，地址为0*5a

接下来上代码，打开万能的GitHub，源码链接在此！

照顾一下打不开的朋友

mlx90614.py

import smbus
from time import sleep

class MLX90614():

    MLX90614_RAWIR1=0x04
    MLX90614_RAWIR2=0x05
    MLX90614_TA=0x06
    MLX90614_TOBJ1=0x07
    MLX90614_TOBJ2=0x08

    MLX90614_TOMAX=0x20
    MLX90614_TOMIN=0x21
    MLX90614_PWMCTRL=0x22
    MLX90614_TARANGE=0x23
    MLX90614_EMISS=0x24
    MLX90614_CONFIG=0x25
    MLX90614_ADDR=0x0E
    MLX90614_ID1=0x3C
    MLX90614_ID2=0x3D
    MLX90614_ID3=0x3E
    MLX90614_ID4=0x3F

    comm_retries = 5
    comm_sleep_amount = 0.1

    def __init__(self, address=0x5a, bus_num=1):
        self.bus_num = bus_num
        self.address = address
        self.bus = smbus.SMBus(bus=bus_num)

    def read_reg(self, reg_addr):
        err = None
        for i in range(self.comm_retries):
            try:
                return self.bus.read_word_data(self.address, reg_addr)
            except IOError as e:
                err = e
                #"Rate limiting" - sleeping to prevent problems with sensor
                #when requesting data too quickly
                sleep(self.comm_sleep_amount)
        #By this time, we made a couple requests and the sensor didn't respond
        #(judging by the fact we haven't returned from this function yet)
        #So let's just re-raise the last IOError we got
        raise err

    def data_to_temp(self, data):
        temp = (data*0.02) - 273.15
        return temp

    def get_amb_temp(self):
        data = self.read_reg(self.MLX90614_TA)
        return self.data_to_temp(data)

    def get_obj_temp(self):
        data = self.read_reg(self.MLX90614_TOBJ1)
        return self.data_to_temp(data)


if __name__ == "__main__":
    sensor = MLX90614()
    print(sensor.get_amb_temp())
    print(sensor.get_obj_temp())

example.py

from mlx90614 import MLX90614

thermometer_address = 0x5a

thermometer = MLX90614(thermometer_address)

print thermometer.get_amb_temp()
print thermometer.get_obj_temp() 

直接运行mlx90614.py就行了。

GitHub地址：https://github.com/CRImier/python-MLX90614