acceleration.py

import smbus

import time

# Get I2C bus
bus = smbus.SMBus(1)

while 1:
    # ADXL345 address, 0x53(83)
    
    # Select bandwidth rate register, 0x2C(44)
    
    #		0x0A(10)	Normal mode, Output data rate = 100 Hz
    
    bus.write_byte_data(0x53, 0x2C, 0x0A)
    
    # ADXL345 address, 0x53(83)
    
    # Select power control register, 0x2D(45)
    
    #		0x08(08)	Auto Sleep disable
    
    bus.write_byte_data(0x53, 0x2D, 0x08)
    
    # ADXL345 address, 0x53(83)
    
    # Select data format register, 0x31(49)
    
    #		0x08(08)	Self test disabled, 4-wire interface
    
    #					Full resolution, Range = +/-2g
    
    bus.write_byte_data(0x53, 0x31, 0x08)
    
    time.sleep(0.5)
    
    # ADXL345 address, 0x53(83)
    
    # Read data back from 0x32(50), 2 bytes
    
    # X-Axis LSB, X-Axis MSB
    
    data0 = bus.read_byte_data(0x53, 0x32)
    
    data1 = bus.read_byte_data(0x53, 0x33)
    
    # Convert the data to 10-bits
    
    xAccl = ((data1 & 0x03) * 256) + data0
    
    if xAccl > 511 :	
    
        xAccl -= 1024
    
    # ADXL345 address, 0x53(83)
    
    # Read data back from 0x34(52), 2 bytes
    
    # Y-Axis LSB, Y-Axis MSB
    
    data0 = bus.read_byte_data(0x53, 0x34)
    
    data1 = bus.read_byte_data(0x53, 0x35)
    
    # Convert the data to 10-bits
    
    yAccl = ((data1 & 0x03) * 256) + data0
    
    if yAccl > 511 :	
    
        yAccl -= 1024
    
    # ADXL345 address, 0x53(83)
    
    # Read data back from 0x36(54), 2 bytes
    
    # Z-Axis LSB, Z-Axis MSB
    
    data0 = bus.read_byte_data(0x53, 0x36)
    
    data1 = bus.read_byte_data(0x53, 0x37)
    
    # Convert the data to 10-bits
    
    zAccl = ((data1 & 0x03) * 256) + data0
    
    if zAccl > 511 :	
    
        zAccl -= 1024
    
    # Output data to screen
    
    print "Acceleration in X-Axis : %d" %xAccl
    
    print "Acceleration in Y-Axis : %d" %yAccl
    
    print "Acceleration in Z-Axis : %d" %zAccl