encoder.Encoder Class Reference

Public Member Functions
	__init__ (self, Pin chA_pin, Pin chB_pin, int tim_num)
	update (self)
	zero (self)
	get_position (self, str unit="counts")
	get_velocity (self, str unit="counts/s")

Public Attributes
	chA_pin = Pin(chA_pin)
	chB_pin = Pin(chB_pin)
int	AR = 65535
	tim_obj = Timer(tim_num, prescaler=0, period=self.AR)
int	position_counts = 0
	prev_count = self.tim_obj.counter()
int	delta = 0
	prev_time = ticks_us()
int	dt = 0
int	velocity_counts_per_s = 0

Static Public Attributes
int	GEAR_RATIO = 3952/33
int	CPR_MOTOR = 12
int	CPR_WHEEL = GEAR_RATIO*CPR_MOTOR
int	RAD_PER_COUNT = 2 * math.pi / CPR_WHEEL
int	WHEEL_RADIUS_MM = 35

Detailed Description

A quadrature encoder decoding interface encapsulated in a Python class. Provides position and velocity.

Constructor & Destructor Documentation

__init__()

encoder.Encoder.__init__	(		self,
		Pin	chA_pin,
		Pin	chB_pin,
		int	tim_num )

Initializes an Encoder object

Member Function Documentation

get_position()

encoder.Encoder.get_position	(		self,
		str	unit = "counts" )

Return position in specified units: "counts", "rad", or "mm".

get_velocity()

encoder.Encoder.get_velocity	(		self,
		str	unit = "counts/s" )

Return velocity in specified units: "counts/s", "rad/s", or "mm/s".

update()

encoder.Encoder.update

(

self

)

Update encoder count and compute velocity.

zero()

encoder.Encoder.zero

(

self

)

Zero the encoder position.

Member Data Documentation

AR

int encoder.Encoder.AR = 65535

chA_pin

encoder.Encoder.chA_pin = Pin(chA_pin)

chB_pin

encoder.Encoder.chB_pin = Pin(chB_pin)

CPR_MOTOR

int encoder.Encoder.CPR_MOTOR = 12

static

CPR_WHEEL

int encoder.Encoder.CPR_WHEEL = GEAR_RATIO*CPR_MOTOR

static

delta

int encoder.Encoder.delta = 0

dt

int encoder.Encoder.dt = 0

GEAR_RATIO

int encoder.Encoder.GEAR_RATIO = 3952/33

static

position_counts

int encoder.Encoder.position_counts = 0

prev_count

encoder.Encoder.prev_count = self.tim_obj.counter()

prev_time

encoder.Encoder.prev_time = ticks_us()

RAD_PER_COUNT

int encoder.Encoder.RAD_PER_COUNT = 2 * math.pi / CPR_WHEEL

static

tim_obj

encoder.Encoder.tim_obj = Timer(tim_num, prescaler=0, period=self.AR)

velocity_counts_per_s

int encoder.Encoder.velocity_counts_per_s = 0

WHEEL_RADIUS_MM

int encoder.Encoder.WHEEL_RADIUS_MM = 35

static

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The documentation for this class was generated from the following file:

• src/encoder.py