# vector3d.py 3D vector class for use in inertial measurement unit drivers
# Author Peter Hinch, Sebastian Plamauer
from utime import sleep_ms
from math import sqrt, degrees, acos, atan2
def default_wait():
'''
delay of 50 ms
'''
sleep_ms(50)
class Vector3d(object):
'''
Represents a vector in a 3D space using Cartesian coordinates.
Internally uses sensor relative coordinates.
Returns vehicle-relative x, y and z values.
'''
def __init__(self, transposition, scaling, update_function):
self._vector = [0, 0, 0]
self._ivector = [0, 0, 0]
self.cal = (0, 0, 0)
self.argcheck(transposition, "Transposition")
self.argcheck(scaling, "Scaling")
if set(transposition) != {0, 1, 2}:
raise ValueError('Transpose indices must be unique and in range 0-2')
self._scale = scaling
self._transpose = transposition
self.update = update_function
def argcheck(self, arg, name):
'''
checks if arguments are of correct length
'''
if len(arg) != 3 or not (type(arg) is list or type(arg) is tuple):
raise ValueError(name + ' must be a 3 element list or tuple')
def calibrate(self, stopfunc, waitfunc=default_wait):
'''
calibration routine, sets cal
'''
self.update()
maxvec = self._vector[:] # Initialise max and min lists with current values
minvec = self._vector[:]
while not stopfunc():
waitfunc()
self.update()
maxvec = list(map(max, maxvec, self._vector))
minvec = list(map(min, minvec, self._vector))
self.cal = tuple(map(lambda a, b: (a + b)/2, maxvec, minvec))
@property
def _calvector(self):
'''
Vector adjusted for calibration offsets
'''
return list(map(lambda val, offset: val - offset, self._vector, self.cal))
@property
def x(self): # Corrected, vehicle relative floating point values
self.update()
return self._calvector[self._transpose[0]] * self._scale[0]
@property
def y(self):
self.update()
return self._calvector[self._transpose[1]] * self._scale[1]
@property
def z(self):
self.update()
return self._calvector[self._transpose[2]] * self._scale[2]
@property
def xyz(self):
self.update()
return (self._calvector[self._transpose[0]] * self._scale[0],
self._calvector[self._transpose[1]] * self._scale[1],
self._calvector[self._transpose[2]] * self._scale[2])
@property
def magnitude(self):
x, y, z = self.xyz # All measurements must correspond to the same instant
return sqrt(x**2 + y**2 + z**2)
@property
def inclination(self):
x, y, z = self.xyz
return degrees(acos(z / sqrt(x**2 + y**2 + z**2)))
@property
def elevation(self):
return 90 - self.inclination
@property
def azimuth(self):
x, y, z = self.xyz
return degrees(atan2(y, x))
# Raw uncorrected integer values from sensor
@property
def ix(self):
return self._ivector[0]
@property
def iy(self):
return self._ivector[1]
@property
def iz(self):
return self._ivector[2]
@property
def ixyz(self):
return self._ivector
@property
def transpose(self):
return tuple(self._transpose)
@property
def scale(self):
return tuple(self._scale)