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CaptainJackeyCaptainJackey
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add pyAI-K210 platform sensors
DS18B20, DHT11, VL53L1X(TOF)
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‎6.pyAI-K210/传感器实验/1.DS18B20温度传感器/ds18x20.py‎

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from modules import onewire
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class DS18X20:
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_CONVERT = const(0x44)
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_RD_SCRATCH = const(0xBE)
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_WR_SCRATCH = const(0x4E)
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_SKIP_ROM = const(0xCC)
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def __init__(self, pin):
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self.device = onewire(pin)
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self.buf = bytearray(9)
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def scan(self):
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return self.device.search(65)
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def convert_temp(self):
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self.device.reset()
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self.device.writebyte(_SKIP_ROM)
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self.device.writebyte(_CONVERT)
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def read_scratch(self, rom):
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self.device.reset()
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self.convert_temp()
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self.device.select(rom)
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self.device.writebyte(_RD_SCRATCH)
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self.buf = self.device.readbuffer(len(self.buf))
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if self.device.crc8(self.buf):
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raise Exception("CRC error")
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return self.buf
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def write_scratch(self, rom, buf):
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self.device.reset()
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self.device.select(rom)
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self.device.writebyte(_WR_SCRATCH)
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self.device.writebuffer(buf)
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def read_temp(self, rom):
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temp = []
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for _rom in rom:
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buf = self.read_scratch(_rom)
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if _rom[0] == 0x10:
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if buf[1]:
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t = buf[0] >> 1 | 0x80
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t = -((~t + 1) & 0xFF)
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else:
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t = buf[0] >> 1
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temp.append(t - 0.25 + (buf[7] - buf[6]) / buf[7])
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else:
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t = buf[1] << 8 | buf[0]
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if t & 0x8000: # sign bit set
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t = -((t ^ 0xFFFF) + 1)
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temp.append(t / 16)
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if len(temp) < 1:
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return -1
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if len(temp) < 2:
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return temp[0]
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return tuple(temp)

‎6.pyAI-K210/传感器实验/1.DS18B20温度传感器/main.py‎

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#实验名称：DS18B20传感器例程
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#实验平台：01Studio pyAI-K210开发板
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#导入相关模块，onewire库请更新至较新版固件
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from fpioa_manager import *
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from micropython import const
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from board import board_info
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from ds18x20 import DS18X20
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import time,lcd,image
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lcd.init() #初始化 LCD
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lcd.clear(lcd.WHITE) #清屏白色
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#初始化DS18B20 GPIO
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fm.register(10, fm.fpioa.GPIOHS2, force=True)
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ds18b20_2 = DS18X20(fm.fpioa.GPIOHS2)
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rom = ds18b20_2.scan()
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while True:
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#采集温度，保留2位小数
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temp = str('%.2f'%ds18b20_2.read_temp(rom))
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#显示字符
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lcd.draw_string(90, 100, "DS18B20 Temp:",lcd.BLACK, lcd.WHITE)
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lcd.draw_string(110, 120, temp+ " C",lcd.BLACK, lcd.WHITE)
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#串口打印
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print(temp+" C")
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time.sleep_ms(1000)#每秒采集1次
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‎6.pyAI-K210/传感器实验/2.DHT11温湿度传感器/dht11.py‎

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import time
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from Maix import GPIO
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class DHT11Result:
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# 'DHT11 sensor result returned by DHT11.read() method'
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ERR_NO_ERROR = 0
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ERR_MISSING_DATA = 1
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ERR_CRC = 2
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error_code = ERR_NO_ERROR
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temperature = -1
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humidity = -1
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def __init__(self, error_code, temperature, humidity):
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self.error_code = error_code
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self.temperature = temperature
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self.humidity = humidity
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def is_valid(self):
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return self.error_code == DHT11Result.ERR_NO_ERROR
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class DHT11:
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def __init__(self, gpio = None):
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# '1DHT11 sensor reader class for MaixPy'
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if gpio != None:
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self._gpio = gpio
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else:
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raise Exception("please input a valid gpio")
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def read(self):
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self._gpio.mode(GPIO.OUT)
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# send initial high
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self.__send_and_sleep(1, 50)
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# pull down to low
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self.__send_and_sleep(0, 20)
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# change to input using pull up
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self._gpio.mode(GPIO.IN)
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# collect data into an array
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data = self.__collect_input()
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# parse lengths of all data pull up periods
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pull_up_lengths = self.__parse_data_pull_up_lengths(data)
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# if bit count mismatch, return error (4 byte data + 1 byte checksum)
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if len(pull_up_lengths) != 40:
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return DHT11Result(DHT11Result.ERR_MISSING_DATA, 0, 0)
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# calculate bits from lengths of the pull up periods
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bits = self.__calculate_bits(pull_up_lengths)
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# we have the bits, calculate bytes
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the_bytes = self.__bits_to_bytes(bits)
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# calculate checksum and check
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checksum = self.__calculate_checksum(the_bytes)
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if the_bytes[4] != checksum:
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return DHT11Result(DHT11Result.ERR_CRC, 0, 0)
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# ok, we have valid data
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# The meaning of the return sensor values
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# the_bytes[0]: humidity int
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# the_bytes[1]: humidity decimal
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# the_bytes[2]: temperature int
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# the_bytes[3]: temperature decimal
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temperature = the_bytes[2] + float(the_bytes[3]) / 10
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humidity = the_bytes[0] + float(the_bytes[1]) / 10
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return DHT11Result(DHT11Result.ERR_NO_ERROR, temperature, humidity)
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def __send_and_sleep(self, output, sleep):
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self._gpio.value(output)
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time.sleep_ms(sleep)
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def __collect_input(self):
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# collect the data while unchanged found
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unchanged_count = 0
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# this is used to determine where is the end of the data
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max_unchanged_count = 100
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last = -1
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data = []
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while True:
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current = self._gpio.value()
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data.append(current)
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if last != current:
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unchanged_count = 0
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last = current
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else:
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unchanged_count += 1
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if unchanged_count > max_unchanged_count:
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break
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return data
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def __parse_data_pull_up_lengths(self, data):
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STATE_INIT_PULL_DOWN = 1
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STATE_INIT_PULL_UP = 2
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STATE_DATA_FIRST_PULL_DOWN = 3
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STATE_DATA_PULL_UP = 4
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STATE_DATA_PULL_DOWN = 5
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state = STATE_INIT_PULL_DOWN
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lengths = [] # will contain the lengths of data pull up periods
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current_length = 0 # will contain the length of the previous period
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for i in range(len(data)):
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current = data[i]
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current_length += 1
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if state == STATE_INIT_PULL_DOWN:
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if current == 0:
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# ok, we got the initial pull down
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state = STATE_INIT_PULL_UP
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continue
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else:
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continue
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if state == STATE_INIT_PULL_UP:
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if current == 1:
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# ok, we got the initial pull up
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state = STATE_DATA_FIRST_PULL_DOWN
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continue
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else:
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continue
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if state == STATE_DATA_FIRST_PULL_DOWN:
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if current == 0:
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# we have the initial pull down, the next will be the data pull up
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state = STATE_DATA_PULL_UP
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continue
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else:
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continue
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if state == STATE_DATA_PULL_UP:
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if current == 1:
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# data pulled up, the length of this pull up will determine whether it is 0 or 1
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current_length = 0
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state = STATE_DATA_PULL_DOWN
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continue
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else:
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continue
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if state == STATE_DATA_PULL_DOWN:
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if current == 0:
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# pulled down, we store the length of the previous pull up period
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lengths.append(current_length)
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state = STATE_DATA_PULL_UP
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continue
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else:
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continue
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return lengths
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def __calculate_bits(self, pull_up_lengths):
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# find shortest and longest period
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shortest_pull_up = 1000
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longest_pull_up = 0
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for i in range(0, len(pull_up_lengths)):
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length = pull_up_lengths[i]
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if length < shortest_pull_up:
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shortest_pull_up = length
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if length > longest_pull_up:
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longest_pull_up = length
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# use the halfway to determine whether the period it is long or short
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halfway = shortest_pull_up + (longest_pull_up - shortest_pull_up) / 2
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bits = []
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for i in range(0, len(pull_up_lengths)):
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bit = False
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if pull_up_lengths[i] > halfway:
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bit = True
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bits.append(bit)
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return bits
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def __bits_to_bytes(self, bits):
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the_bytes = []
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byte = 0
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for i in range(0, len(bits)):
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byte = byte << 1
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if (bits[i]):
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byte = byte | 1
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else:
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byte = byte | 0
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if ((i + 1) % 8 == 0):
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the_bytes.append(byte)
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byte = 0
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return the_bytes
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def __calculate_checksum(self, the_bytes):
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return the_bytes[0] + the_bytes[1] + the_bytes[2] + the_bytes[3] & 255

‎6.pyAI-K210/传感器实验/2.DHT11温湿度传感器/main.py‎

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# DTH11温湿度传感器
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# 实验平台：01Studio pyAI-K210开发板
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import time
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from fpioa_manager import fm
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from Maix import GPIO
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from dht11 import DHT11
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while True:
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# initialize GPIOHS3 using io 11
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fm.register(11, fm.fpioa.GPIOHS3, force=True)
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gpio = GPIO(GPIO.GPIOHS3, GPIO.OUT)
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# read data using gpio
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instance = DHT11(gpio)
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try:
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while True:
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result = instance.read()
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if result.is_valid():
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print("Temperature: %-3.1f C" % result.temperature)
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print("Humidity: %-3.1f %%" % result.humidity)
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time.sleep_ms(1000)
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except Exception as e:
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print(e)

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