add support library for MPU925x 10-DOF IMU sensor

fixes fossasia#59

PSL/Peripherals.py

@@ -383,7 +383,6 @@ def __captureStart__(self,address,location,sample_length,total_samples,tg):
         """
         Blocking call that starts fetching data from I2C sensors like an oscilloscope fetches voltage readings
         You will then have to call `__retrievebuffer__` to fetch this data, and `__dataProcessor` to process and return separate channels
-        
         refer to `capture` if you want a one-stop solution.
         
         .. tabularcolumns:: |p{3cm}|p{11cm}|

PSL/SENSORS/MPU925x.py

@@ -0,0 +1,200 @@
+# -*- coding: utf-8; mode: python; indent-tabs-mode: t; tab-width:4 -*-
+from numpy import int16,std
+from Kalman import KalmanFilter
+
+def connect(route,**args):
+	return MPU925x(route,**args)
+
+class MPU925x():
+	'''
+	Mandatory members:
+	GetRaw : Function called by Graphical apps. Must return values stored in a list
+	NUMPLOTS : length of list returned by GetRaw. Even single datapoints need to be stored in a list before returning
+	PLOTNAMES : a list of strings describing each element in the list returned by GetRaw. len(PLOTNAMES) = NUMPLOTS
+	name : the name of the sensor shown to the user
+	params:
+		A dictionary of function calls(single arguments only) paired with list of valid argument values. (Primitive. I know.)
+		These calls can be used for one time configuration settings
+
+	'''
+	INT_PIN_CFG = 0x37
+	GYRO_CONFIG = 0x1B
+	ACCEL_CONFIG = 0x1C
+	GYRO_SCALING= [131,65.5,32.8,16.4]
+	ACCEL_SCALING=[16384,8192,4096,2048]
+	AR=3
+	GR=3
+	NUMPLOTS=7
+	PLOTNAMES = ['Ax','Ay','Az','Temp','Gx','Gy','Gz']
+	ADDRESS = 0x68
+	AK8963_ADDRESS =0x0C
+	AK8963_CNTL = 0x0A
+	name = 'Accel/gyro'
+	def __init__(self,I2C,**args):
+		self.I2C=I2C
+		self.ADDRESS = args.get('address',self.ADDRESS)
+		self.name = 'Accel/gyro'
+		self.params={'powerUp':None,'setGyroRange':[250,500,1000,2000],'setAccelRange':[2,4,8,16],'KalmanFilter':[.01,.1,1,10,100,1000,10000,'OFF']}
+		self.setGyroRange(2000)
+		self.setAccelRange(16)
+		'''
+		try:
+			self.I2C.configI2C(400e3)
+		except:
+			pass
+		'''
+		self.powerUp()
+		self.K=None
+
+
+
+	def KalmanFilter(self,opt):
+		if opt=='OFF':
+			self.K=None
+			return
+		noise=[[]]*self.NUMPLOTS
+		for a in range(500):
+			vals=self.getRaw()
+			for b in range(self.NUMPLOTS):noise[b].append(vals[b])
+
+		self.K=[None]*7
+		for a in range(self.NUMPLOTS):
+			sd = std(noise[a])
+			self.K[a] = KalmanFilter(1./opt, sd**2)
+
+	def getVals(self,addr,bytes):
+		vals = self.I2C.readBulk(self.ADDRESS,addr,bytes) 
+		return vals
+
+	def powerUp(self):
+		self.I2C.writeBulk(self.ADDRESS,[0x6B,0])
+
+	def setGyroRange(self,rs):
+		self.GR=self.params['setGyroRange'].index(rs)
+		self.I2C.writeBulk(self.ADDRESS,[self.GYRO_CONFIG,self.GR<<3])
+
+	def setAccelRange(self,rs):
+		self.AR=self.params['setAccelRange'].index(rs)
+		self.I2C.writeBulk(self.ADDRESS,[self.ACCEL_CONFIG,self.AR<<3])
+
+	def getRaw(self):
+		'''
+		This method must be defined if you want GUIs to use this class to generate 
+		plots on the fly.
+		It must return a set of different values read from the sensor. such as X,Y,Z acceleration.
+		The length of this list must not change, and must be defined in the variable NUMPLOTS.
+		
+		GUIs will generate as many plots, and the data returned from this method will be appended appropriately
+		'''
+		vals=self.getVals(0x3B,14)
+		if vals:
+			if len(vals)==14:
+				raw=[0]*7
+				for a in range(3):raw[a] = 1.*int16(vals[a*2]<<8|vals[a*2+1])/self.ACCEL_SCALING[self.AR]
+				for a in range(4,7):raw[a] = 1.*int16(vals[a*2]<<8|vals[a*2+1])/self.GYRO_SCALING[self.GR]
+				raw[3] = int16(vals[6]<<8|vals[7])/340. + 36.53
+				if not self.K:
+					return raw
+				else:
+					for b in range(self.NUMPLOTS):
+						self.K[b].input_latest_noisy_measurement(raw[b])
+						raw[b]=self.K[b].get_latest_estimated_measurement()
+					return raw
+
+			else:
+				return False
+		else:
+			return False
+
+	def getAccel(self):
+		'''
+		Return a list of 3 values for acceleration vector
+		
+		'''
+		vals=self.getVals(0x3B,6)
+		ax=int16(vals[0]<<8|vals[1])
+		ay=int16(vals[2]<<8|vals[3])
+		az=int16(vals[4]<<8|vals[5])
+		return [ax/65535.,ay/65535.,az/65535.]
+
+	def getTemp(self):
+		'''
+		Return temperature
+		'''
+		vals=self.getVals(0x41,6)
+		t=int16(vals[0]<<8|vals[1])
+		return t/65535.
+
+	def getGyro(self):
+		'''
+		Return a list of 3 values for angular velocity vector
+		
+		'''
+		vals=self.getVals(0x43,6)
+		ax=int16(vals[0]<<8|vals[1])
+		ay=int16(vals[2]<<8|vals[3])
+		az=int16(vals[4]<<8|vals[5])
+		return [ax/65535.,ay/65535.,az/65535.]
+
+	def getMag(self):
+		'''
+		Return a list of 3 values for magnetic field vector
+		
+		'''
+		vals=self.I2C.readBulk(self.AK8963_ADDRESS,0x03,7) #6+1 . 1(ST2) should not have bit 4 (0x8) true. It's ideally 16 . overflow bit
+		ax=int16(vals[0]<<8|vals[1])
+		ay=int16(vals[2]<<8|vals[3])
+		az=int16(vals[4]<<8|vals[5])
+		if not vals[6]&0x08:return [ax/65535.,ay/65535.,az/65535.]
+		else: return None
+
+
+	def WhoAmI(self):
+		'''
+		Returns the ID . 
+		It is 71 for MPU9250 . 
+		'''
+		v = self.I2C.readBulk(self.ADDRESS,0x75,1)[0]
+		if v not in [0x71,0x73]:return 'Error %s'%hex(v)
+
+
+		if v==0x73:return 'MPU9255 %s'%hex(v)
+		elif v==0x71:return 'MPU9250 %s'%hex(v)
+
+
+	def WhoAmI_AK8963(self):
+		'''
+		Returns the ID fo magnetometer AK8963 if found. 
+		It should be 0x48. 
+		'''
+		self.initMagnetometer()
+		v= self.I2C.readBulk(self.AK8963_ADDRESS,0,1) [0]
+		if v==0x48:return 'AK8963 at %s'%hex(v)
+		else: return 'AK8963 not found. returned :%s'%hex(v)
+
+	def initMagnetometer(self):
+		'''
+		For MPU925x with integrated magnetometer.
+		It's called a 10 DoF sensor, but technically speaking , 
+		the 3-axis Accel , 3-Axis Gyro, temperature sensor are integrated in one IC, and the 3-axis magnetometer is implemented in a 
+		separate IC which can be accessed via an I2C passthrough.
+		
+		Therefore , in order to detect the magnetometer via an I2C scan, the passthrough must first be enabled on IC#1 (Accel,gyro,temp)
+		'''
+		self.I2C.writeBulk(self.ADDRESS,[self.INT_PIN_CFG,0x22]) #I2C passthrough
+		self.I2C.writeBulk(self.AK8963_ADDRESS,[self.AK8963_CNTL,0]) #power down mag
+		self.I2C.writeBulk(self.AK8963_ADDRESS,[self.AK8963_CNTL,(1<<4)|6]) #mode   (0=14bits,1=16bits) <<4 | (2=8Hz , 6=100Hz)
+
+
+
+if __name__ == "__main__":
+	from PSL import sciencelab
+	I = sciencelab.connect()
+	A = connect(I.I2C) 
+	t,x,y,z = I.I2C.capture(A.ADDRESS,0x43,6,5000,1000,'int') 
+	#print (t,x,y,z)
+	from pylab import *
+	plot(t,x)
+	plot(t,y)
+	plot(t,z)
+	show()