power sensor class and test added

power_sensor.py

@@ -0,0 +1,38 @@
+import smbus
+
+class power_sensor:
+	def __init__(self, bus = 1, addr = 0x40):
+		self.bus = smbus.SMBus(bus)
+		self.addr = addr
+
+		bytes = [(0x1000 >> 8) & 0xFF, 0x1000 & 0xFF]
+		self.bus.write_i2c_block_data(self.addr, 0x05, bytes)
+		config = 0x2000 | 0x1800 | 0x0400 | 0x0018 | 0x0007
+		bytes = [(config >> 8) & 0xFF, config & 0xFF]
+		self.bus.write_i2c_block_data(self.addr, 0x00, bytes)
+
+	def shunt_voltage_mv(self):
+		data = self.bus.read_i2c_block_data(self.addr, 0x01)
+		voltage = data[0] * 256 + data[1]
+		return voltage * 0.01
+
+	def current_ma(self):
+		data = self.bus.read_i2c_block_data(self.addr, 0x04)
+		if(data[0] >> 7 == 1):
+			current = data[0] * 256 + data[1]
+			if(current & (1 << 15)):
+				current = current - (1 << 16)
+		else:
+			current = (data[0] << 8) | (data[1])
+		return current / 10
+
+	def power_mw(self):
+		data = self.bus.read_i2c_block_data(self.addr, 0x03)
+		if(data[0] >> 7 == 1):
+			power = data[0] * 256 + data[1]
+			if(power & (1 << 15)):
+				power = power - (1 << 16)
+		else:
+			power = (data[0] << 8) | (data[1])
+		return power / 2
+

power_sensor_test.py

@@ -0,0 +1,14 @@
+#!/usr/bin/python2
+from power_sensor import power_sensor
+from time import sleep
+
+ps = power_sensor(1, 0x40)
+while True:
+	voltage = ps.shunt_voltage_mv()
+	print str(voltage) + " mV"
+	current = ps.current_ma()
+	print str(current) + " mA"
+	power = ps.power_mw()
+	print str(power) + " mW"
+	sleep(1)
+