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Copy pathMAX30105.py
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102 lines (82 loc) · 3.61 KB
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from smbus import SMBus
import time
class MAX30105(object):
def __init__(self, bus, address):
self.address = address
self.bus = SMBus(bus)
self._led_mode = None
self._pulse_width_set = None
try:
self.bus.read_byte(self.address)
except:
print("Sensor not found. Check wiring.")
raise SystemExit()
else:
print("Found MAX30105 Particle Sensor on bus {}: [{}]".format(bus, hex(self.address)))
def read_register(self, REG, n_bytes=1):
self.bus.write_byte(self.address, REG)
return self.bus.read_i2c_block_data(self.address, REG, n_bytes)
def write_register(self, REG, VALUE):
self.bus.write_i2c_block_data(self.address, REG, [VALUE])
return
def bit_mask(self, REG, MASK, NEW_VALUE):
newCONTENTS = (self.byte_to_int(self.read_register(REG)) & MASK) | NEW_VALUE
self.write_register(REG, newCONTENTS)
return
def setup_sensor(self, LED_MODE=2, LED_POWER=0x1F, PULSE_WIDTH=0x01):
self.bit_mask(0x09, 0xBF, 0x40)
time.sleep(1)
# 3: 69 (15-bit), 2: 118 (16-bit), 1: 215 (17-bit), 0: 411 (18-bit)
self.bit_mask(0x0A, 0xFC, PULSE_WIDTH)
self._pulse_width_set = PULSE_WIDTH
if LED_MODE not in [1, 2, 3]:
raise ValueError('wrong LED mode:{0}!'.format(LED_MODE))
elif LED_MODE == 1:
self.bit_mask(0x09, 0xF8, 0x02)
self.write_register(0x0C, LED_POWER)
elif LED_MODE == 2:
self.bit_mask(0x09, 0xF8, 0x03)
self.write_register(0x0C, LED_POWER)
self.write_register(0x0D, LED_POWER)
elif LED_MODE == 3:
self.bit_mask(0x09, 0xF8, 0x07)
self.write_register(0x0C, LED_POWER)
self.write_register(0x0D, LED_POWER)
self.write_register(0x0E, LED_POWER)
self.write_register(0x11, 0b00100001)
self.write_register(0x12, 0b00000011)
self._led_mode = LED_MODE
self.bit_mask(0x0A, 0xE3, 0x0C) # sampl. rate: 50
# 50: 0x00, 100: 0x04, 200: 0x08, 400: 0x0C,
# 800: 0x10, 1000: 0x14, 1600: 0x18, 3200: 0x1C
self.bit_mask(0x0A, 0x9F, 0x60) # ADC range: 2048
# 2048: 0x00, 4096: 0x20, 8192: 0x40, 16384: 0x60
self.bit_mask(0x08, ~0b11100000, 0x00) # FIFO sample avg: (no)
# 1: 0x00, 2: 0x20, 4: 0x40, 8: 0x60, 16: 0x80, 32: 0xA0
self.bit_mask(0x08, 0xEF, 0x01) # FIFO rollover: enable
# 0x00/0x01: dis-/enable
self.write_register(0x04, 0)
self.write_register(0x05, 0)
self.write_register(0x06, 0)
def set_red_led_power(self, LED_POWER):
self.bit_mask(0x09, 0xF8, 0x02)
self.write_register(0x0C, LED_POWER)
def set_ir_led_power(self, LED_POWER):
self.bit_mask(0x09, 0xF8, 0x03)
self.write_register(0x0D, LED_POWER)
def set_green_led_power(self, LED_POWER):
self.bit_mask(0x09, 0xF8, 0x07)
self.write_register(0x0E, LED_POWER)
def byte_to_int(self, byte_data):
return int.from_bytes(byte_data, byteorder='big', signed=False)
def read_sensor(self, pointer_position):
self.write_register(0x06, pointer_position)
fifo_bytes = self.read_register(0x07, self._led_mode * 3)
red_int = self.byte_to_int(fifo_bytes[0:3])
IR_int = self.byte_to_int(fifo_bytes[3:6])
green_int = self.byte_to_int(fifo_bytes[6:9])
return red_int, IR_int, green_int
def clear_fifo(self):
self.write_register(0x04, 0)
self.write_register(0x05, 0)
self.write_register(0x06, 0)