mirror of
https://github.com/supleed2/ELEC60013-ES-CW1.git
synced 2024-09-19 20:06:17 +00:00
136 lines
5 KiB
Python
136 lines
5 KiB
Python
"""Library for interacting with LIS3DH triple-axis accelerometer."""
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from importlib.resources import read_text
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from re import S
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from tabnanny import check
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import smbus2
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from time import sleep
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# Register addresses
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_CTRL_REG1 = bytes([0x20])
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_CTRL_REG2 = bytes([0x21])
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_CTRL_REG3 = bytes([0x22])
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_CTRL_REG4 = bytes([0x23])
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_CTRL_REG5 = bytes([0x24])
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_CTRL_REG6 = bytes([0x25])
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_REF_REG = bytes([0x26])
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_STATUS_REG = bytes([0x27])
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_OUT_X_L = bytes([0x28])
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_OUT_X_H = bytes([0x29])
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_OUT_Y_L = bytes([0x2A])
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_OUT_Y_H = bytes([0x2B])
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_OUT_Z_L = bytes([0x2C])
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_OUT_Z_H = bytes([0x2D])
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_INT1_CFG = bytes([0x30])
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_INT1_SRC = bytes([0x31])
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_INT1_THS = bytes([0x32])
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_INT1_DURATION = bytes([0x33])
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_INT2_CFG = bytes([0x34])
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_INT2_SRC = bytes([0x35])
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_INT2_THS = bytes([0x36])
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_INT2_DURATION = bytes([0x37])
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_CLICK_CFG = bytes([0x38])
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# Config flags
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SAMPLERATE_1HZ = bytes([0x17])
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SAMPLERATE_10HZ = bytes([0x27])
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SAMPLERATE_25HZ = bytes([0x37])
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HP_DISABLE = bytes([0x00])
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CTRL_REG3_V = bytes([0x40])
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CTRL_REG4_V = bytes([0x00]) # sensitivity set to 2g
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CTRL_REG5_V = bytes([0x08])
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INT1_THS_V = bytes([0x16]) # free-fall threshold at 350 mg
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INT1_DURATION_V = bytes([0x03])
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INT1_CFG_V = bytes([0x95])
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EMPTY = bytes([0x00])
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class LIS3DH:
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def __init__(self, i2cBus, samplerate=10, i2cAddress=0x18):
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sleep(0.005)
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self.i2c = i2cBus
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self.addr = i2cAddress
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self.samplerate = samplerate
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i2cBus.pec = True # enable smbus2 Packet Error Checking
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sample_modes = {
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0:0x0, 1:0x1, 10:0x2, 25:0x3, 50:0x4,
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100:0x5, 200:0x6, 400:0x7
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}
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# Check if user-entered values are correct
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if samplerate in sample_modes:
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self.samplerate = sample_modes[samplerate]
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else:
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raise Exception("Invalid sample rate.")
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# Configure all registers in +-2g mode
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c0 = smbus2.i2c_msg.write(self.addr, [0x20,(sample_modes[samplerate]<<4)|0xF]) # Initialise in low power mode
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c1 = smbus2.i2c_msg.write(self.addr, [0x21,0x0A])
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c2 = smbus2.i2c_msg.write(self.addr, [0x22,0x40])
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c3 = smbus2.i2c_msg.write(self.addr, [0x23,0x00])
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c4 = smbus2.i2c_msg.write(self.addr, [0x24,0x0A])
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c5 = smbus2.i2c_msg.write(self.addr, [0x25,0x20])
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c6 = smbus2.i2c_msg.write(self.addr, [0x2E,0x00])
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c7 = smbus2.i2c_msg.write(self.addr, [0x30,0x95])
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c8 = smbus2.i2c_msg.write(self.addr, [0x32,0x16])
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c9 = smbus2.i2c_msg.write(self.addr, [0x33,0x03])
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c10 = smbus2.i2c_msg.write(self.addr, [0x34,0x3F])
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c11 = smbus2.i2c_msg.write(self.addr, [0x36,0x32])
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c12 = smbus2.i2c_msg.write(self.addr, [0x24,0x0A]) # Configure 0x24 again
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self.i2c.i2c_rdwr(c0,c1,c2,c3,c4,c5,c6,c7,c8,c9,c10,c11,c12)
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def resetint1(self) -> bool:
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'''Read INT1_SRC to reset it after an interrupt event.'''
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int1_src_loc = smbus2.i2c_msg.write(self.addr, [0x31])
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read_int1_src = smbus2.i2c_msg.read(self.addr, 1)
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self.i2c.i2c_rdwr(int1_src_loc,read_int1_src)
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if read_int1_src.buf[0] != None:
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return True
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else:
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return False
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def resetint2(self) -> bool:
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'''Read INT2_SRC to reset it after an interrupt event.'''
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int2_src_loc = smbus2.i2c_msg.write(self.addr, [0x35])
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read_int2_src = smbus2.i2c_msg.read(self.addr, 1)
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self.i2c.i2c_rdwr(int2_src_loc,read_int2_src)
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if read_int2_src.buf[0] != None:
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return True
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else:
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return False
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def readAll(self) -> list:
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'''Read acceleration data from all axes. Returns values as a list [X,Y,Z].'''
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check_status = smbus2.i2c_msg.write(self.addr, [0x27])
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x = smbus2.i2c_msg.read(self.addr, 1)
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y = smbus2.i2c_msg.read(self.addr, 1)
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z = smbus2.i2c_msg.read(self.addr, 1)
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prepare_x = smbus2.i2c_msg.write(self.addr, [0x29])
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prepare_y = smbus2.i2c_msg.write(self.addr, [0x2B])
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prepare_z = smbus2.i2c_msg.write(self.addr, [0x2D])
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status = smbus2.i2c_msg.read(self.addr, 1)
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self.i2c.i2c_rdwr(check_status, status)
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while status.buf[0][0] & 0b1111 != 0b1111: # Wait for data to be available
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sleep(0.001)
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self.i2c.i2c_rdwr(check_status, status)
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if status.buf[0][0] & 0b1111 == 0b1111: # If data is available, read
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self.i2c.i2c_rdwr(prepare_x, x)
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self.i2c.i2c_rdwr(prepare_y, y)
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self.i2c.i2c_rdwr(prepare_z, z)
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X = int.from_bytes(x.buf[0],"big")
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Y = int.from_bytes(y.buf[0],"big")
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Z = int.from_bytes(z.buf[0],"big")
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# Convert from binary 2s complement to useful data
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new_values = []
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for D in [X,Y,Z]:
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MSB = D >> 7
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if MSB == 1:
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res = (-128 + (D - 128))*self.resolution/128
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else:
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res = (D*self.resolution)/128
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new_values.append(res)
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return new_values
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else:
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return None # Should never get here lol |