Код Python для SHT35, используемый с мультиплексором TCA9548A - PullRequest
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Код Python для SHT35, используемый с мультиплексором TCA9548A

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/ 21 марта 2019

У меня есть рабочий код для чтения BMP280, подключенного к TCA9548A. 

csvfile = "/home/pi/My-logs/temp_181.txt"

import time

from datetime import datetime

import smbus

# Get I2C bus
bus3 = smbus.SMBus(3)
bus4 = smbus.SMBus(4)

while True:
    #Reading Data from i2c bus3 3
    b1 = bus3.read_i2c_block_data(0x77, 0x88, 24)

    # Convert the data
    # Temp coefficents
    dig_T1 = b1[1] * 256 + b1[0]
    dig_T2 = b1[3] * 256 + b1[2]
    if dig_T2 > 32767 :
        dig_T2 -= 65536
    dig_T3 = b1[5] * 256 + b1[4]
    if dig_T3 > 32767 :
        dig_T3 -= 65536

    # Pressure coefficents
    dig_P1 = b1[7] * 256 + b1[6]
    dig_P2 = b1[9] * 256 + b1[8]
    if dig_P2 > 32767 :
        dig_P2 -= 65536
    dig_P3 = b1[11] * 256 + b1[10]
    if dig_P3 > 32767 :
        dig_P3 -= 65536
    dig_P4 = b1[13] * 256 + b1[12]
    if dig_P4 > 32767 :
        dig_P4 -= 65536
    dig_P5 = b1[15] * 256 + b1[14]
    if dig_P5 > 32767 :
        dig_P5 -= 65536
    dig_P6 = b1[17] * 256 + b1[16]
    if dig_P6 > 32767 :
        dig_P6 -= 65536
    dig_P7 = b1[19] * 256 + b1[18]
    if dig_P7 > 32767 :
        dig_P7 -= 65536
    dig_P8 = b1[21] * 256 + b1[20]
    if dig_P8 > 32767 :
        dig_P8 -= 65536
    dig_P9 = b1[23] * 256 + b1[22]
    if dig_P9 > 32767 :
        dig_P9 -= 65536

    # BMP280 address, 0x77(118)
    # Select Control measurement register, 0xF4(244)
    #       0x27(39)    Pressure and Temperature Oversampling rate = 1
    #                   Normal mode
    bus3.write_byte_data(0x77, 0xF4, 0x27)

    # BMP280 address, 0x77(118)
    # Select Configuration register, 0xF5(245)
    #       0xA0(00)    Stand_by time = 1000 ms
    bus3.write_byte_data(0x77, 0xF5, 0xA0)

    # BMP280 address, 0x77(118)
    # Read data back from 0xF7(247), 8 bytes
    # Pressure MSB, Pressure LSB, Pressure xLSB, Temperature MSB, Temperature LSB
    # Temperature xLSB, Humidity MSB, Humidity LSB
    data = bus3.read_i2c_block_data(0x77, 0xF7, 8)

    # Convert pressure and temperature data to 19-bits
    adc_p = ((data[0] * 65536) + (data[1] * 256) + (data[2] & 0xF0)) / 16
    adc_t = ((data[3] * 65536) + (data[4] * 256) + (data[5] & 0xF0)) / 16

    # Temperature offset calculations
    var1 = ((adc_t) / 16384.0 - (dig_T1) / 1024.0) * (dig_T2)
    var2 = (((adc_t) / 131072.0 - (dig_T1) / 8192.0) * ((adc_t)/131072.0 - (dig_T1)/8192.0)) * (dig_T3)
    t_fine = (var1 + var2)
    cTemp = (var1 + var2) / 5120.0
    fTemp = cTemp * 1.8 + 32

    # Pressure offset calculations
    var1 = (t_fine / 2.0) - 64000.0
    var2 = var1 * var1 * (dig_P6) / 32768.0
    var2 = var2 + var1 * (dig_P5) * 2.0
    var2 = (var2 / 4.0) + ((dig_P4) * 65536.0)
    var1 = ((dig_P3) * var1 * var1 / 524288.0 + ( dig_P2) * var1) / 524288.0
    var1 = (1.0 + var1 / 32768.0) * (dig_P1)
    p = 1048576.0 - adc_p
    p = (p - (var2 / 4096.0)) * 6250.0 / var1
    var1 = (dig_P9) * p * p / 2147483648.0
    var2 = p * (dig_P8) / 32768.0
    pressure = (p + (var1 + var2 + (dig_P7)) / 16.0) / 100

    # Output data to screen. Reading sensor on i2c bus 3
    date = datetime.now()
    timestamp = date.strftime("%d/%m/%Y %H:%M:%S")

    values_15 = timestamp, round(cTemp, 2), round(pressure, 2)

    with open(csvfile, "a") as f:
         f.write (str(values_15) + "\n")
         print (values_15) 
         f.close()
    time.sleep(10)

Теперь я ищу код для считывания датчика SHT35, подключенного к TCA9548A. Может быть, в этом коде нужно изменить только несколько вещей, чтобы прочитать датчик?

Лист данных SHT35

https://datasheet.lcsc.com/szlcsc/Sensirion-SHT35-DIS-B_C90161.pdf

Я использую датчик Grove.

http://wiki.seeedstudio.com/Grove-I2C_High_Accuracy_Temp&Humi_Sensor-SHT35/

Надеюсь, кто-нибудь сможет мне помочь.

Louis

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