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sps30.py
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sps30.py
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import sys
import threading
import logging
from time import sleep
from queue import Queue
from datetime import datetime
from i2c.i2c import I2C
# I2C commands
CMD_START_MEASUREMENT = [0x00, 0x10]
CMD_STOP_MEASUREMENT = [0x01, 0x04]
CMD_READ_DATA_READY_FLAG = [0x02, 0x02]
CMD_READ_MEASURED_VALUES = [0x03, 0x00]
CMD_SLEEP = [0x10, 0x01]
CMD_WAKEUP = [0x11, 0x03]
CMD_START_FAN_CLEANING = [0x56, 0x07]
CMD_AUTO_CLEANING_INTERVAL = [0x80, 0x04]
CMD_PRODUCT_TYPE = [0xD0, 0x02]
CMD_SERIAL_NUMBER = [0xD0, 0x33]
CMD_FIRMWARE_VERSION = [0xD1, 0x00]
CMD_READ_STATUS_REGISTER = [0xD2, 0x06]
CMD_CLEAR_STATUS_REGISTER = [0xD2, 0x10]
CMD_RESET = [0xD3, 0x04]
# Length of response in bytes
NBYTES_READ_DATA_READY_FLAG = 3
NBYTES_MEASURED_VALUES_FLOAT = 60 # IEEE754 float
NBYTES_MEASURED_VALUES_INTEGER = 30 # unsigned 16 bit integer
NBYTES_AUTO_CLEANING_INTERVAL = 6
NBYTES_PRODUCT_TYPE = 12
NBYTES_SERIAL_NUMBER = 48
NBYTES_FIRMWARE_VERSION = 3
NBYTES_READ_STATUS_REGISTER = 6
# Packet size including checksum byte [data1, data2, checksum]
PACKET_SIZE = 3
# Size of each measurement data packet (PMx) including checksum bytes, in bytes
SIZE_FLOAT = 6 # IEEE754 float
SIZE_INTEGER = 3 # unsigned 16 bit integer
class SPS30:
def __init__(self, bus: int = 1, address: int = 0x69, sampling_period: int = 1, logger: str = None):
self.logger = None
if logger:
self.logger = logging.getLogger(logger)
self.sampling_period = sampling_period
self.i2c = I2C(bus, address)
self.__data = Queue(maxsize=20)
self.__valid = {
"mass_density": False,
"particle_count": False,
"particle_size": False
}
def crc_calc(self, data: list) -> int:
crc = 0xFF
for i in range(2):
crc ^= data[i]
for _ in range(8, 0, -1):
if crc & 0x80:
crc = (crc << 1) ^ 0x31
else:
crc = crc << 1
# The checksum only contains 8-bit,
# so the calculated value has to be masked with 0xFF
return (crc & 0x0000FF)
def firmware_version(self) -> str:
self.i2c.write(CMD_FIRMWARE_VERSION)
data = self.i2c.read(NBYTES_FIRMWARE_VERSION)
if self.crc_calc(data[:2]) != data[2]:
return "CRC mismatched"
return ".".join(map(str, data[:2]))
def product_type(self) -> str:
self.i2c.write(CMD_PRODUCT_TYPE)
data = self.i2c.read(NBYTES_PRODUCT_TYPE)
result = ""
for i in range(0, NBYTES_PRODUCT_TYPE, 3):
if self.crc_calc(data[i:i+2]) != data[i+2]:
return "CRC mismatched"
result += "".join(map(chr, data[i:i+2]))
return result
def serial_number(self) -> str:
self.i2c.write(CMD_SERIAL_NUMBER)
data = self.i2c.read(NBYTES_SERIAL_NUMBER)
result = ""
for i in range(0, NBYTES_SERIAL_NUMBER, PACKET_SIZE):
if self.crc_calc(data[i:i+2]) != data[i+2]:
return "CRC mismatched"
result += "".join(map(chr, data[i:i+2]))
return result
def read_status_register(self) -> dict:
self.i2c.write(CMD_READ_STATUS_REGISTER)
data = self.i2c.read(NBYTES_READ_STATUS_REGISTER)
status = []
for i in range(0, NBYTES_READ_STATUS_REGISTER, PACKET_SIZE):
if self.crc_calc(data[i:i+2]) != data[i+2]:
return "CRC mismatched"
status.extend(data[i:i+2])
binary = '{:032b}'.format(
status[0] << 24 | status[1] << 16 | status[2] << 8 | status[3])
speed_status = "too high/ too low" if int(binary[10]) == 1 else "ok"
laser_status = "out of range" if int(binary[26]) == 1 else "ok"
fan_status = "0 rpm" if int(binary[27]) == 1 else "ok"
return {
"speed_status": speed_status,
"laser_status": laser_status,
"fan_status": fan_status
}
def clear_status_register(self) -> None:
self.i2c.write(CMD_CLEAR_STATUS_REGISTER)
def read_data_ready_flag(self) -> bool:
self.i2c.write(CMD_READ_DATA_READY_FLAG)
data = self.i2c.read(NBYTES_READ_DATA_READY_FLAG)
if self.crc_calc(data[:2]) != data[2]:
if self.logger:
self.logger.warning(
"'read_data_ready_flag' CRC mismatched!" +
f" Data: {data[:2]}" +
f" Calculated CRC: {self.crc_calc(data[:2])}" +
f" Expected: {data[2]}")
else:
print(
"'read_data_ready_flag' CRC mismatched!" +
f" Data: {data[:2]}" +
f" Calculated CRC: {self.crc_calc(data[:2])}" +
f" Expected: {data[2]}")
return False
return True if data[1] == 1 else False
def sleep(self) -> None:
self.i2c.write(CMD_SLEEP)
def wakeup(self) -> None:
self.i2c.write(CMD_WAKEUP)
def start_fan_cleaning(self) -> None:
self.i2c.write(CMD_START_FAN_CLEANING)
def read_auto_cleaning_interval(self) -> int:
self.i2c.write(CMD_AUTO_CLEANING_INTERVAL)
data = self.i2c.read(NBYTES_AUTO_CLEANING_INTERVAL)
interval = []
for i in range(0, NBYTES_AUTO_CLEANING_INTERVAL, 3):
if self.crc_calc(data[i:i+2]) != data[i+2]:
return "CRC mismatched"
interval.extend(data[i:i+2])
return (interval[0] << 24 | interval[1] << 16 | interval[2] << 8 | interval[3])
def write_auto_cleaning_interval_days(self, days: int) -> int:
seconds = days * 86400 # 1day = 86400sec
interval = []
interval.append((seconds & 0xff000000) >> 24)
interval.append((seconds & 0x00ff0000) >> 16)
interval.append((seconds & 0x0000ff00) >> 8)
interval.append(seconds & 0x000000ff)
data = CMD_AUTO_CLEANING_INTERVAL
data.extend([interval[0], interval[1]])
data.append(self.crc_calc(data[2:4]))
data.extend([interval[2], interval[3]])
data.append(self.crc_calc(data[5:7]))
self.i2c.write(data)
sleep(0.05)
return self.read_auto_cleaning_interval()
def reset(self) -> None:
self.i2c.write(CMD_RESET)
def __ieee754_number_conversion(self, data: int) -> float:
binary = "{:032b}".format(data)
sign = int(binary[0:1])
exp = int(binary[1:9], 2) - 127
divider = 0
if exp < 0:
divider = abs(exp)
exp = 0
mantissa = binary[9:]
real = int(('1' + mantissa[:exp]), 2)
decimal = mantissa[exp:]
dec = 0.0
for i in range(len(decimal)):
dec += int(decimal[i]) / (2**(i+1))
if divider == 0:
return round((((-1)**(sign) * real) + dec), 3)
else:
return round((((-1)**(sign) * real) + dec) / pow(2, divider), 3)
def __mass_density_measurement(self, data: list) -> dict:
category = ["pm1.0", "pm2.5", "pm4.0", "pm10"]
density = {
"pm1.0": 0.0,
"pm2.5": 0.0,
"pm4.0": 0.0,
"pm10": 0.0
}
for block, (pm) in enumerate(category):
pm_data = []
for i in range(0, SIZE_FLOAT, PACKET_SIZE):
offset = (block * SIZE_FLOAT) + i
if self.crc_calc(data[offset:offset+2]) != data[offset+2]:
if self.logger:
self.logger.warning(
"'__mass_density_measurement' CRC mismatched!" +
f" Data: {data[offset:offset+2]}" +
f" Calculated CRC: {self.crc_calc(data[offset:offset+2])}" +
f" Expected: {data[offset+2]}")
else:
print(
"'__mass_density_measurement' CRC mismatched!" +
f" Data: {data[offset:offset+2]}" +
f" Calculated CRC: {self.crc_calc(data[offset:offset+2])}" +
f" Expected: {data[offset+2]}")
self.__valid["mass_density"] = False
return {}
pm_data.extend(data[offset:offset+2])
density[pm] = self.__ieee754_number_conversion(
pm_data[0] << 24 | pm_data[1] << 16 | pm_data[2] << 8 | pm_data[3])
self.__valid["mass_density"] = True
return density
def __particle_count_measurement(self, data: list) -> dict:
category = ["pm0.5", "pm1.0", "pm2.5", "pm4.0", "pm10"]
count = {
"pm0.5": 0.0,
"pm1.0": 0.0,
"pm2.5": 0.0,
"pm4.0": 0.0,
"pm10": 0.0
}
for block, (pm) in enumerate(category):
pm_data = []
for i in range(0, SIZE_FLOAT, PACKET_SIZE):
offset = (block * SIZE_FLOAT) + i
if self.crc_calc(data[offset:offset+2]) != data[offset+2]:
if self.logger:
self.logger.warning(
"'__particle_count_measurement' CRC mismatched!" +
f" Data: {data[offset:offset+2]}" +
f" Calculated CRC: {self.crc_calc(data[offset:offset+2])}" +
f" Expected: {data[offset+2]}")
else:
print(
"'__particle_count_measurement' CRC mismatched!" +
f" Data: {data[offset:offset+2]}" +
f" Calculated CRC: {self.crc_calc(data[offset:offset+2])}" +
f" Expected: {data[offset+2]}")
self.__valid["particle_count"] = False
return {}
pm_data.extend(data[offset:offset+2])
count[pm] = self.__ieee754_number_conversion(
pm_data[0] << 24 | pm_data[1] << 16 | pm_data[2] << 8 | pm_data[3])
self.__valid["particle_count"] = True
return count
def __particle_size_measurement(self, data: list) -> float:
size = []
for i in range(0, SIZE_FLOAT, PACKET_SIZE):
if self.crc_calc(data[i:i+2]) != data[i+2]:
if self.logger:
self.logger.warning(
"'__particle_size_measurement' CRC mismatched!" +
f" Data: {data[i:i+2]}" +
f" Calculated CRC: {self.crc_calc(data[i:i+2])}" +
f" Expected: {data[i+2]}")
else:
print(
"'__particle_size_measurement' CRC mismatched!" +
f" Data: {data[i:i+2]}" +
f" Calculated CRC: {self.crc_calc(data[i:i+2])}" +
f" Expected: {data[i+2]}")
self.__valid["particle_size"] = False
return 0.0
size.extend(data[i:i+2])
self.__valid["particle_size"] = True
return self.__ieee754_number_conversion(size[0] << 24 | size[1] << 16 | size[2] << 8 | size[3])
def __read_measured_value(self) -> None:
while True:
try:
if not self.read_data_ready_flag():
continue
self.i2c.write(CMD_READ_MEASURED_VALUES)
data = self.i2c.read(NBYTES_MEASURED_VALUES_FLOAT)
if self.__data.full():
self.__data.get()
result = {
"sensor_data": {
"mass_density": self.__mass_density_measurement(data[:24]),
"particle_count": self.__particle_count_measurement(data[24:54]),
"particle_size": self.__particle_size_measurement(data[54:]),
"mass_density_unit": "ug/m3",
"particle_count_unit": "#/cm3",
"particle_size_unit": "um"
},
"timestamp": int(datetime.now().timestamp())
}
self.__data.put(result if all(self.__valid.values()) else {})
except KeyboardInterrupt:
if self.logger:
self.logger.warning("Stopping measurement...")
else:
print("Stopping measurement...")
self.stop_measurement()
sys.exit()
except Exception as e:
if self.logger:
self.logger.warning(f"{type(e).__name__}: {e}")
else:
print(f"{type(e).__name__}: {e}")
finally:
sleep(self.sampling_period)
def start_measurement(self) -> None:
data_format = {
"IEEE754_float": 0x03,
"unsigned_16_bit_integer": 0x05
}
data = CMD_START_MEASUREMENT
data.extend([data_format["IEEE754_float"], 0x00])
data.append(self.crc_calc(data[2:4]))
self.i2c.write(data)
sleep(0.05)
self.__run()
def get_measurement(self) -> dict:
if self.__data.empty():
return {}
return self.__data.get()
def stop_measurement(self) -> None:
self.i2c.write(CMD_STOP_MEASUREMENT)
self.i2c.close()
def __run(self) -> None:
threading.Thread(target=self.__read_measured_value,
daemon=True).start()