2016-12-20 21:09:01 +00:00
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'''
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Created on Dec 19, 2016
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@author: klaehn
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'''
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import smbus
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class PowerSensor(object):
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'''
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Power sensor wrapper
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'''
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def __init__(self, bus = 1, addr = 0x40):
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self.__bus = smbus.SMBus(bus)
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self.__addr = addr
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value = [(0x1000 >> 8) & 0xFF, 0x1000 & 0xFF]
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self.__bus.write_i2c_block_data(self.__addr, 0x05, value)
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config = 0x2000 | 0x1800 | 0x0400 | 0x0018 | 0x0007
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value = [(config >> 8) & 0xFF, config & 0xFF]
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self.__bus.write_i2c_block_data(self.__addr, 0x00, value)
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def shunt_voltage_mv(self):
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''' Read the voltage at the shunt resistor [mV] '''
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data = self.__bus.read_i2c_block_data(self.__addr, 0x01)
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voltage = data[0] * 256 + data[1]
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return voltage * 0.01
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def current_ma(self):
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''' Read the current [mA] '''
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data = self.__bus.read_i2c_block_data(self.__addr, 0x04)
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if data[0] >> 7 == 1:
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current = data[0] * 256 + data[1]
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if current & (1 << 15):
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current = current - (1 << 16)
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else:
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current = (data[0] << 8) | (data[1])
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return current / 10
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def power_mw(self):
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''' Read the power [mW] '''
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data = self.__bus.read_i2c_block_data(self.__addr, 0x03)
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if data[0] >> 7 == 1:
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power = data[0] * 256 + data[1]
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if power & (1 << 15):
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power = power - (1 << 16)
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else:
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power = (data[0] << 8) | (data[1])
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return power / 2
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