(3)ESP32 Python 製作一個辦公室溫度計

ScottX發表於2022-01-20
Python

因為經常在辦公室裡面不知道實際室內溫度是多少，所以用ESP32做了一個工具來進行溫度&溼度的監測。在之前的文章當中，已經完成了ESP32的資料上雲工作，如果要進行溫度/溼度的檢測。從原理上就是給ESP32連線對應的感測器，並把感測器的資料上報到阿里雲物聯網平臺。
我們先來看看效果
image

這樣的話，每天上班前在家裡可以先看看辦公室空調是否已經把公司的溫度提升上去，如果沒有提升上去。那說明可能空調有問題，今日的取暖只能靠抖了。
下面我們說說，這個實現怎麼搞。首先在阿里雲IOT平臺上，對我們之前的產品新增2個功能分別為當前溼度和當前溫度。

image

實現步驟如下：

  1. 根據所使用的硬體，進行board.json的配置。 因為我們的溫度感測器使用的是sht3x, 使用I2C，在board.json的配置如下：
{
    "name": "haasedu",
    "version": "1.0.0",
    "io": { 
      "sht3x": {
        "type": "I2C",
        "port": 0,
        "addrWidth": 7,
        "freq": 400000,
        "mode": "master",
        "devAddr": 68
      } 
    },
    "debugLevel": "ERROR",
    "repl": "disable"
  }
  1. 實現程式碼
from driver import I2C   
import sht3x        
def report_iot_data(temperature, humidity ):
    upload_data = {'params': ujson.dumps({
        'CurrentHumidity': humidity, 'CurrentTemperature':temperature
    })
    }  
    device.postProps(upload_data)
    print('UPDATE IOT SUCCESS!!!')
    
def get_light_temp_humi():
    
    temperature = humitureDev.getTemperature()        
    humidity = humitureDev.getHumidity()    
    report_iot_data(temperature, humidity)
    return temperature, humidity
i2cObj = I2C() 
i2cObj.open("sht3x")   
humitureDev = sht3x.SHT3X(i2cObj)    
    
while True:
    data = get_light_temp_humi()    
    utime.sleep(3)

進行燒錄就可以了。
獲取溫度溼潤還需要使用Haas團隊寫的一個驅動，程式碼如下
sht3x.py

"""
Copyright (C) 2015-2021 Alibaba Group Holding Limited
    MicroPython's driver for CHT8305
    Author: HaaS
    Date:   2021/09/14
"""
from micropython import const
import utime
from driver import I2C
'''
# sht3x commands definations
# read serial number:                            CMD_READ_SERIALNBR  0x3780     
# read status register:                          CMD_READ_STATUS     0xF32D     
# clear status register:                         CMD_CLEAR_STATUS    0x3041  
# enabled heater:                                CMD_HEATER_ENABLE   0x306D   
# disable heater:                                CMD_HEATER_DISABLE  0x3066      
# soft reset:                                    CMD_SOFT_RESET      0x30A2      
# accelerated response time:                     CMD_ART             0x2B32
# break, stop periodic data acquisition mode:    CMD_BREAK           0x3093
# measurement: polling, high repeatability:      CMD_MEAS_POLLING_H  0x2400
# measurement: polling, medium repeatability:    CMD_MEAS_POLLING_M  0x240B
# measurement: polling, low repeatability:       CMD_MEAS_POLLING_L  0x2416
'''
class SHT3X(object):
    # i2cDev should be an I2C object and it should be opened before __init__ is called
    def __init__(self, i2cDev):
        self._i2cDev = None
        if not isinstance(i2cDev, I2C):
            raise ValueError("parameter is not an I2C object")
        # make AHB21B's internal object points to _i2cDev
        self._i2cDev = i2cDev
        self.start()
    def start(self):
        # make sure AHB21B's internal object is valid before I2C operation
        if self._i2cDev is None:
            raise ValueError("invalid I2C object")
        # send clear status register command - 0x3041 - CMD_CLEAR_STATUS
        cmd = bytearray(2)
        cmd[0] = 0x30
        cmd[1] = 0x41
        self._i2cDev.write(cmd)
        # wait for 20ms
        utime.sleep_ms(20)
        return 0
    def getTempHumidity(self):
        if self._i2cDev is None:
            raise ValueError("invalid I2C object")
        tempHumidity = [-1, 2]
        
        # start measurement: polling, medium repeatability - 0x240B - CMD_MEAS_POLLING_M   
        # if you want to adjust measure repeatability, you can send the following commands:
        # high repeatability: 0x2400 - CMD_MEAS_POLLING_H
        # low repeatability: 0x2416  - CMD_MEAS_POLLING_L
        cmd = bytearray(2)
        cmd[0] = 0x24
        cmd[1] = 0x0b
        self._i2cDev.write(cmd)
        # must wait for a little before the measurement finished
        utime.sleep_ms(20)
        dataBuffer = bytearray(6)
        # read the measurement result
        self._i2cDev.read(dataBuffer)
        # print(dataBuffer)
        # calculate real temperature and humidity according to SHT3X-DIS' data sheet
        temp = (dataBuffer[0]<<8) | dataBuffer[1]
        humi = (dataBuffer[3]<<8) | dataBuffer[4]
        tempHumidity[1] = humi * 0.0015259022
        tempHumidity[0] = -45.0 + (temp) * 175.0 / (0xFFFF - 1)
        return tempHumidity
    def getTemperature(self):
        data = self.getTempHumidity()
        return data[0]
    def getHumidity(self):
        data = self.getTempHumidity()
        return data[1]
    def stop(self):
        if self._i2cDev is None:
            raise ValueError("invalid I2C object")
        # stop periodic data acquisition mode
        cmd = bytearray(3)
        cmd[0] = 0x30
        cmd[1] = 0x93
        self._i2cDev.write(cmd)
        # wait for a little while
        utime.sleep_ms(20)
        self._i2cDev = None
        return 0
    def __del__(self):
        print('sht3x __del__')
if __name__ == "__main__":
    '''
    The below i2c configuration is needed in your board.json.
    "sht3x": {
        "type": "I2C",
        "port": 1,
        "addrWidth": 7,
        "freq": 400000,
        "mode": "master",
        "devAddr": 68
    },
    '''
    print("Testing sht3x ...")
    i2cDev = I2C()
    i2cDev.open("sht3x")
    sht3xDev = SHT3X(i2cDev)
    '''
    # future usage:
    i2cDev = I2C("sht3x")
    sht3xDev = sht3x.SHT3X(i2cDev)
    '''
    temperature = sht3xDev.getTemperature()
    print("The temperature is: %f" % temperature)
    humidity = sht3xDev.getHumidity()
    print("The humidity is: %f" % humidity)
    print("Test sht3x done!")

將程式程式碼燒錄到開發板後，裝置會聯網，並且每3秒上報一次資料。釋出的資料， 我們可以在阿里雲物聯網平臺上的裝置的物模型資料中看到。
image
關於board.json的部分，需要根據自己採用的溫度/溼度感測器，調整對應的GPIO的編號就行。

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