grovepi/Software/Python/grove_6axis_acc_compass/lsm303d.py

#!/usr/bin/env python
#
# GrovePi Library for using the Grove - 6-Axis Accelerometer&Compass v2.0(http://www.seeedstudio.com/depot/Grove-6Axis-AccelerometerCompass-v20-p-2476.html)
#
# This sensor uses LSM303D chip and the library works in Python for the Raspberry Pi
#
# The GrovePi connects the Raspberry Pi and Grove sensors.  You can learn more about GrovePi here:  http://www.dexterindustries.com/GrovePi
#
# Have a question about this library?  Ask on the forums here:  http://forum.dexterindustries.com/c/grovepi
#

# Released under the MIT license (http://choosealicense.com/licenses/mit/).
# For more information see https://github.com/DexterInd/GrovePi/blob/master/LICENSE

import time,sys
import RPi.GPIO as GPIO
import smbus
import math

# use the bus that matches your raspi version
rev = GPIO.RPI_REVISION
if rev == 2 or rev == 3:
    bus = smbus.SMBus(1)
else:
    bus = smbus.SMBus(0)

class lsm303d:
	# LSM303 Address definitions
	LSM303D_ADDR	= 0x1E  # assuming SA0 grounded

	# LSM303 Register definitions
	TEMP_OUT_L		= 0x05
	TEMP_OUT_H		= 0x06
	STATUS_REG_M	= 0x07
	OUT_X_L_M 		= 0x08
	OUT_X_H_M 		= 0x09
	OUT_Y_L_M 		= 0x0A
	OUT_Y_H_M 		= 0x0B
	OUT_Z_L_M 		= 0x0C
	OUT_Z_H_M 		= 0x0D
	WHO_AM_I		= 0x0F
	INT_CTRL_M		= 0x12
	INT_SRC_M		= 0x13
	INT_THS_L_M		= 0x14
	INT_THS_H_M		= 0x15
	OFFSET_X_L_M	= 0x16
	OFFSET_X_H_M	= 0x17
	OFFSET_Y_L_M	= 0x18
	OFFSET_Y_H_M	= 0x19
	OFFSET_Z_L_M	= 0x1A
	OFFSET_Z_H_M	= 0x1B
	REFERENCE_X 	= 0x1C
	REFERENCE_Y 	= 0x1D
	REFERENCE_Z 	= 0x1E
	CTRL_REG0 		= 0x1F
	CTRL_REG1 		= 0x20
	CTRL_REG2		= 0x21
	CTRL_REG3 		= 0x22
	CTRL_REG4 		= 0x23
	CTRL_REG5 		= 0x24
	CTRL_REG6 		= 0x25
	CTRL_REG7 		= 0x26
	STATUS_REG_A	= 0x27
	OUT_X_L_A 		= 0x28
	OUT_X_H_A 		= 0x29
	OUT_Y_L_A 		= 0x2A
	OUT_Y_H_A 		= 0x2B
	OUT_Z_L_A 		= 0x2C
	OUT_Z_H_A 		= 0x2D
	FIFO_CTRL		= 0x2E
	FIFO_SRC		= 0x2F
	IG_CFG1			= 0x30
	IG_SRC1			= 0x31
	IG_THS1			= 0x32
	IG_DUR1			= 0x33
	IG_CFG2			= 0x34
	IG_SRC2			= 0x35
	IG_THS2			= 0x36
	IG_DUR2			= 0x37
	CLICK_CFG		= 0x38
	CLICK_SRC		= 0x39
	CLICK_THS		= 0x3A
	TIME_LIMIT		= 0x3B
	TIME_LATENCY	= 0x3C
	TIME_WINDOW		= 0x3D
	ACT_THS			= 0x3E
	ACT_DUR			= 0x3F

	MAG_SCALE_2 	= 0x00 #full-scale is +/-2Gauss
	MAG_SCALE_4 	= 0x20 #+/-4Gauss
	MAG_SCALE_8 	= 0x40 #+/-8Gauss
	MAG_SCALE_12 	= 0x60 #+/-12Gauss

	ACCELE_SCALE 	= 2

	X 				= 0
	Y 				= 1
	Z 				= 2

	# Set up the sensor
	def __init__(self,):
		self.write_reg(0x57, self.CTRL_REG1)				# 0x57 = ODR=50hz, all accel axes on
		self.write_reg((3<<6)|(0<<3), self.CTRL_REG2)  	# set full-scale
		self.write_reg(0x00, self.CTRL_REG3)  			# no interrupt
		self.write_reg(0x00, self.CTRL_REG4)  			# no interrupt
		self.write_reg((4<<2), self.CTRL_REG5)  			# 0x10 = mag 50Hz output rate
		self.write_reg(self.MAG_SCALE_2, self.CTRL_REG6)		# magnetic scale = +/-1.3Gauss
		self.write_reg(0x00, self.CTRL_REG7)  			# 0x00 = continouous conversion mode
		time.sleep(.005)

	# get the status of the sensor
	def status(self):
		if self.read_reg(self.WHO_AM_I) !=73:
			return -1
		return 1

	# Write data to a reg on the I2C device
	def write_reg(self,data,reg):
		bus.write_byte_data(self.LSM303D_ADDR, reg, data)

	# Read data from the sensor
	def read_reg(self,reg):
		return bus.read_byte_data(self.LSM303D_ADDR, reg)

	# Check if compass is ready
	def isMagReady(self):
		if self.read_reg(self.STATUS_REG_M)&0x03!=0:
			return 1
		return 0

	# Get raw accelerometer values
	def getAccel(self):
		raw_accel=[0,0,0]
		raw_accel[0]=((self.read_reg(self.OUT_X_H_A)<<8)|self.read_reg(self.OUT_X_L_A))
		raw_accel[1]=((self.read_reg(self.OUT_Y_H_A)<<8)|self.read_reg(self.OUT_Y_L_A))
		raw_accel[2]=((self.read_reg(self.OUT_Z_H_A)<<8)|self.read_reg(self.OUT_Z_L_A))

		#2's compiment
		for i in range(3):
			if raw_accel[i]>32767:
				raw_accel[i]=raw_accel[i]-65536

		return raw_accel

	# Get accelerometer values in g
	def getRealAccel(self):
		realAccel=[0.0,0.0,0.0]
		accel=self.getAccel()
		for i in range(3):
			realAccel[i] = round(accel[i] / math.pow(2, 15) * self.ACCELE_SCALE,3)
		return realAccel

	# Get compass raw values
	def getMag(self):
		raw_mag=[0,0,0]
		raw_mag[0]=(self.read_reg(self.OUT_X_H_M)<<8)|self.read_reg(self.OUT_X_L_M)
		raw_mag[1]=(self.read_reg(self.OUT_Y_H_M)<<8)|self.read_reg(self.OUT_Y_L_M)
		raw_mag[2]=(self.read_reg(self.OUT_Z_H_M)<<8)|self.read_reg(self.OUT_Z_L_M)

		#2's compiment
		for i in range(3):
			if raw_mag[i]>32767:
				raw_mag[i]=raw_mag[i]-65536

		return raw_mag

	# Get heading from the compass
	def getHeading(self):
		magValue=self.getMag()
		heading = 180*math.atan2(magValue[self.Y], magValue[self.X])/math.pi#  // assume pitch, roll are 0

		if (heading <0):
			heading += 360

		return round(heading,3)

	def getTiltHeading(self):
		magValue=self.getMag()
		accelValue=self.getRealAccel()

		X=self.X
		Y=self.Y
		Z=self.Z

		pitch = math.asin(-accelValue[X])

		print(accelValue[Y],pitch,math.cos(pitch),accelValue[Y]/math.cos(pitch),math.asin(accelValue[Y]/math.cos(pitch)))
		roll = math.asin(accelValue[Y]/math.cos(pitch))

		xh = magValue[X] * math.cos(pitch) + magValue[Z] * math.sin(pitch)
		yh = magValue[X] * math.sin(roll) * math.sin(pitch) + magValue[Y] * math.cos(roll) - magValue[Z] * math.sin(roll) * math.cos(pitch)
		zh = -magValue[X] * (roll) * math.sin(pitch) + magValue[Y] * math.sin(roll) + magValue[Z] * math.cos(roll) * math.cos(pitch)
		heading = 180 * math.atan2(yh, xh)/math.pi

		if (yh >= 0):
			return heading
		else:
			return (360 + heading)

if __name__ == "__main__":
	acc_mag=lsm303d()
	while True:
		print(acc_mag.getRealAccel())

		while True:
			if acc_mag.isMagReady():
				break
		print(acc_mag.getHeading())

		# Do not use, math error
		# print acc_mag.getTiltHeading()