溫濕度感測器實作 – NSHT30數位式溫濕度感測器

 溫濕度感測器實作 – NSHT30數位式溫濕度感測器

電路圖

 

程式列表

MicroPython - NSHT30.py

"""   NSHT30   Number Name   ------------    6      VCC    5    4      AL    3      SDA    2      SCL    1      GND   ------------ """   from machine import Pin, I2C import utime   NSHT30_I2C_ADDRESS = 0x44 # I2C address B 0x44 ADDR (pin 2) connected to GND # NSHT30_I2C_ADDRESS = 0x45 # I2C address B 0x45 ADDR (pin 2) connected to VDD   class NSHT30:   """   NSHT30 sensor driver in pure python based on I2C bus   """   POLYNOMIAL = 0x131  # P(x) = x^8 + x^5 + x^4 + 1 = 100110001     ALERT_PENDING_MASK = 0x8000 # 15   HEATER_MASK        = 0x2000 # 13   RH_ALERT_MASK      = 0x0800 # 11   T_ALERT_MASK       = 0x0400 # 10   RESET_MASK         = 0x0010 # 4   CMD_STATUS_MASK    = 0x0002 # 1   WRITE_STATUS_MASK  = 0x0001 # 0     #NSHT30驅動代碼   MEAS_SINGLE_H_CMD  = b'\x24\x00' # measurement: SINGLE Mode high repeatability   MEAS_SINGLE_M_CMD  = b'\x24\x0B' # measurement: SINGLE Mode medium repeatability   MEAS_SINGLE_L_CMD  = b'\x24\x16' # measurement: SINGLE Mode low repeatability   MEAS_PERI_05_H_CMD = b'\x20\x32' # measurement: periodic Mode 0.5 mps high repeatability   MEAS_PERI_05_M_CMD = b'\x20\x24' # measurement: periodic Mode 0.5 mps medium repeatability   MEAS_PERI_05_L_CMD = b'\x20\x2F' # measurement: periodic Mode 0.5 mps low repeatability   MEAS_PERI_1_H_CMD  = b'\x21\x30' # measurement: periodic Mode 1 mps high repeatability   MEAS_PERI_1_M_CMD  = b'\x21\x26' # measurement: periodic Mode 1 mps medium repeatability   MEAS_PERI_1_L_CMD  = b'\x21\x2D' # measurement: periodic Mode 1 mps low repeatability   MEAS_PERI_2_H_CMD  = b'\x22\x36' # measurement: periodic Mode 2 mps high repeatability   MEAS_PERI_2_M_CMD  = b'\x22\x20' # measurement: periodic Mode 2 mps medium repeatability   MEAS_PERI_2_L_CMD  = b'\x22\x2B' # measurement: periodic Mode 2 mps low repeatability   MEAS_PERI_4_H_CMD  = b'\x23\x34' # measurement: periodic Mode 4 mps high repeatability   MEAS_PERI_4_M_CMD  = b'\x23\x22' # measurement: periodic Mode 4 mps medium repeatability   MEAS_PERI_4_L_CMD  = b'\x23\x29' # measurement: periodic Mode 4 mps low repeatability   MEAS_PERI_10_H_CMD = b'\x27\x37' # measurement: periodic Mode 10 mps high repeatability   MEAS_PERI_10_M_CMD = b'\x27\x21' # measurement: periodic Mode 10 mps medium repeatability   MEAS_PERI_10_L_CMD = b'\x27\x2A' # measurement: periodic Mode 10 mps low repeatability   PERIODIC_MODE_READ_CMD = b'\xE0\x00'   PERIODIC_MODE_BREAK_CMD = b'\x30\x93'     STATUS_CMD = b'\xF3\x2D'   RESET_CMD = b'\x30\xA2'   CLEAR_STATUS_CMD = b'\x30\x41'   ENABLE_HEATER_CMD = b'\x30\x6D'   DISABLE_HEATER_CMD = b'\x30\x66'     HAL_OK = 0   HAL_ERROR = 1     def __init__(self, i2c=None, i2c_address=None):     # construct an I2C bus     if i2c is None:       i2c = I2C(0,I2C.MASTER,baudrate=100000)     #Create I2C0 Master Mode, Baudrate=100kHz     if i2c_address is None:       i2c_address = 0x44     self.i2c = i2c     self.i2c_addr = i2c_address     utime.sleep_ms(50)     def is_present(self):     """     Return true if the sensor is correctly conneced, False otherwise     """     return self.i2c_addr in self.i2c.scan()     def _check_crc(self, data):     # calculates 8-Bit checksum with given polynomial     crc = 0xFF       for b in data[:-1]:       crc ^= b       for _ in range(8, 0, -1):         if crc & 0x80:           crc = (crc << 1) ^ NSHT30.POLYNOMIAL         else:           crc <<= 1     crc_to_check = data[-1]     return crc_to_check == crc     def send_cmd(self, cmd_request, response_size=6, read_delay_ms=100):     """     Send a command to the sensor and read (optionally) the response     The responsed data is validated by CRC     """     try:       self.i2c.send(cmd_request, self.i2c_addr)  # write the given buffer to the peripheral       if not response_size:         return       data =  bytearray(response_size) #       utime.sleep_ms(read_delay_ms)       self.i2c.recv(data,self.i2c_addr)         for i in range(response_size//3):         if not self._check_crc(data[i*3:(i+1)*3]):  # pos 2 and 5 are CRC           raise NSHT30Error(SHT30Error.CRC_ERROR)       if data == bytearray(response_size):         raise NSHT30Error(SHT30Error.DATA_ERROR)       return data     except OSError:       raise NSHT30Error(SHT30Error.BUS_ERROR)     except Exception as ex:       raise ex     def clear_status(self):     """     Clear the status register     """     return self.send_cmd(NSHT30.CLEAR_STATUS_CMD, None)     def reset(self):     """     Send a soft-reset to the sensor     """     return self.send_cmd(NSHT30.RESET_CMD, None)     def status(self, raw=False):     """     Get the sensor status register.     It returns a int value or the bytearray(3) if raw==True     """     data = self.send_cmd(NSHT30.STATUS_CMD, 3, read_delay_ms=20)       if raw:       return data       status_register = data[0] << 8 | data[1]     return status_register     def measure(self, cmd, read_delay_ms=100, raw=False):     """     If raw==True returns a bytearrya(6) with sensor direct measurement otherwise     It gets the temperature (T) and humidity (RH) measurement and return them.       The units are Celsius and percent     """     if cmd is None:       cmd = NSHT30.MEAS_SINGLE_L_CMD     data = self.send_cmd(cmd, 6, read_delay_ms) # read 6 bytes       if raw:       return data       t_celsius = (((data[0] << 8 | data[1]) * 175) / 0xFFFF) - 45     rh = (((data[3] << 8 | data[4]) * 100.0) / 0xFFFF)     return t_celsius, rh   class NSHT30Error(Exception):   """   Custom exception for errors on sensor management   """   BUS_ERROR = 0x01   DATA_ERROR = 0x02   CRC_ERROR = 0x03     def __init__(self, error_code=None):     self.error_code = error_code     super().__init__(self.get_message())     def get_message(self):     if self.error_code == NSHT30Error.BUS_ERROR:       return "Bus error"     elif self.error_code == NSHT30Error.DATA_ERROR:       return "Data error"     elif self.error_code == NSHT30Error.CRC_ERROR:       return "CRC error"     else:       return "Unknown error"

 

MicroPython - NSHT30_main.py

"""             NSHT30   ePy-Lite  Number Name   -------------------------   3V3        6      VCC              5              4      AL   P16_SDA0   3      SDA   P17_SCL0   2      SCL   GND        1      GND   ------------------------- """   from machine import Switch  #Get button KEY library from machine import Pin, LED, I2C ,UART import utime from NSHT30 import NSHT30   BLEOUT = False DEBUG = True KeyADone = None   I2C_FREQ = 100000   NSHT30_I2C_ADDRESS = 0x44 # I2C address B 0x44 ADDR (pin 2) connected to GND # NSHT30_I2C_ADDRESS = 0x45 # I2C address B 0x45 ADDR (pin 2) connected to VDD   INTERVAL = 5000  # millisecond   def key_int():   global KeyADone   KeyADone = True   # Start Function if __name__ == '__main__':   ledY = LED('ledy')   ledR = LED('ledr')   ledY.off()   ledR.off()     KeyA = Switch('keya')    # Create button A   KeyA.callback(key_int)   KeyADone = False     i2c = I2C(0,I2C.MASTER,baudrate=I2C_FREQ)     # Create I2C0 Master Mode, Baudrate=100kHz   sensor = NSHT30(i2c)     if(BLEOUT):     ble = UART(1,115200)     ble.write('AT+MODE_DATA\r\n')     utime.sleep(2)   print("Start humidity measurement.")   lastTime=0   while True:     currTime = utime.ticks_ms()     if (currTime - lastTime > INTERVAL):       lastTime = currTime       ledY.toggle()       temperature, humidity = sensor.measure(sensor.MEAS_SINGLE_L_CMD)       print('Temperature: %.2f*C, Humidity: %.2f%%' %(temperature,humidity))       if(BLEOUT):         ble.write('T = {}*C, H = {}%\r\n'.format (temperature,humidity))       ledY.toggle()       if KeyADone == True:      # Press A Key       break     if(BLEOUT):     ble.deinit()   i2c.deinit() # close the connection to the module   KeyA.callback(None)   print("Exit humidity measurement.")

 

執行結果

Thonny訊息列表

 

LightBlue APP畫面

 

 

參考文獻

l   溫濕度感測器NSHT30使用設計指南(AN-12-0010) - https://www.novosns.com/files/ApplicationNote_wenshiduchuanganqiNSHT30shiyongshejizhinan.pdf