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Add simple two DC motor robot class and example.

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Tony DiCola
2016-01-08 09:11:16 +00:00
parent 70e6bd7ed8
commit 75fef4095e
3 changed files with 186 additions and 1 deletions
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examples/Robot.py Normal file
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# Simple two DC motor robot class. Exposes a simple LOGO turtle-like API for
# moving a robot forward, backward, and turning. See RobotTest.py for an
# example of using this class.
# Author: Tony DiCola
# License: MIT License https://opensource.org/licenses/MIT
import time
import atexit
from Adafruit_MotorHAT import Adafruit_MotorHAT
class Robot(object):
def __init__(self, addr=0x60, left_id=1, right_id=2, left_trim=0, right_trim=0,
stop_at_exit=True):
"""Create an instance of the robot. Can specify the following optional
parameters:
- addr: The I2C address of the motor HAT, default is 0x60.
- left_id: The ID of the left motor, default is 1.
- right_id: The ID of the right motor, default is 2.
- left_trim: Amount to offset the speed of the left motor, can be positive
or negative and use useful for matching the speed of both
motors. Default is 0.
- right_trim: Amount to offset the speed of the right motor (see above).
- stop_at_exit: Boolean to indicate if the motors should stop on program
exit. Default is True (highly recommended to keep this
value to prevent damage to the bot on program crash!).
"""
# Initialize motor HAT and left, right motor.
self._mh = Adafruit_MotorHAT(addr)
self._left = self._mh.getMotor(left_id)
self._right = self._mh.getMotor(right_id)
self._left_trim = left_trim
self._right_trim = right_trim
# Start with motors turned off.
self._left.run(Adafruit_MotorHAT.RELEASE)
self._right.run(Adafruit_MotorHAT.RELEASE)
# Configure all motors to stop at program exit if desired.
if stop_at_exit:
atexit.register(self.stop)
def _left_speed(self, speed):
"""Set the speed of the left motor, taking into account its trim offset.
"""
assert 0 <= speed <= 255, 'Speed must be a value between 0 to 255 inclusive!'
speed += self._left_trim
speed = max(0, min(255, speed)) # Constrain speed to 0-255 after trimming.
self._left.setSpeed(speed)
def _right_speed(self, speed):
"""Set the speed of the right motor, taking into account its trim offset.
"""
assert 0 <= speed <= 255, 'Speed must be a value between 0 to 255 inclusive!'
speed += self._right_trim
speed = max(0, min(255, speed)) # Constrain speed to 0-255 after trimming.
self._right.setSpeed(speed)
def stop(self):
"""Stop all movement."""
self._left.run(Adafruit_MotorHAT.RELEASE)
self._right.run(Adafruit_MotorHAT.RELEASE)
def forward(self, speed, seconds=None):
"""Move forward at the specified speed (0-255). Will start moving
forward and return unless a seconds value is specified, in which
case the robot will move forward for that amount of time and then stop.
"""
# Set motor speed and move both forward.
self._left_speed(speed)
self._right_speed(speed)
self._left.run(Adafruit_MotorHAT.FORWARD)
self._right.run(Adafruit_MotorHAT.FORWARD)
# If an amount of time is specified, move for that time and then stop.
if seconds is not None:
time.sleep(seconds)
self.stop()
def backward(self, speed, seconds=None):
"""Move backward at the specified speed (0-255). Will start moving
backward and return unless a seconds value is specified, in which
case the robot will move backward for that amount of time and then stop.
"""
# Set motor speed and move both backward.
self._left_speed(speed)
self._right_speed(speed)
self._left.run(Adafruit_MotorHAT.BACKWARD)
self._right.run(Adafruit_MotorHAT.BACKWARD)
# If an amount of time is specified, move for that time and then stop.
if seconds is not None:
time.sleep(seconds)
self.stop()
def right(self, speed, seconds=None):
"""Spin to the right at the specified speed. Will start spinning and
return unless a seconds value is specified, in which case the robot will
spin for that amount of time and then stop.
"""
# Set motor speed and move both forward.
self._left_speed(speed)
self._right_speed(speed)
self._left.run(Adafruit_MotorHAT.FORWARD)
self._right.run(Adafruit_MotorHAT.BACKWARD)
# If an amount of time is specified, move for that time and then stop.
if seconds is not None:
time.sleep(seconds)
self.stop()
def left(self, speed, seconds=None):
"""Spin to the left at the specified speed. Will start spinning and
return unless a seconds value is specified, in which case the robot will
spin for that amount of time and then stop.
"""
# Set motor speed and move both forward.
self._left_speed(speed)
self._right_speed(speed)
self._left.run(Adafruit_MotorHAT.BACKWARD)
self._right.run(Adafruit_MotorHAT.FORWARD)
# If an amount of time is specified, move for that time and then stop.
if seconds is not None:
time.sleep(seconds)
self.stop()

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examples/RobotTest.py Normal file
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# Simple two DC motor robot class usage example.
# Author: Tony DiCola
# License: MIT License https://opensource.org/licenses/MIT
import time
# Import the Robot.py file (must be in the same directory as this file!).
import Robot
# Set the trim offset for each motor (left and right). This is a value that
# will offset the speed of movement of each motor in order to make them both
# move at the same desired speed. Because there's no feedback the robot doesn't
# know how fast each motor is spinning and the robot can pull to a side if one
# motor spins faster than the other motor. To determine the trim values move the
# robot forward slowly (around 100 speed) and watch if it veers to the left or
# right. If it veers left then the _right_ motor is spinning faster so try
# setting RIGHT_TRIM to a small negative value, like -5, to slow down the right
# motor. Likewise if it veers right then adjust the _left_ motor trim to a small
# negative value. Increase or decrease the trim value until the bot moves
# straight forward/backward.
LEFT_TRIM = 0
RIGHT_TRIM = 0
# Create an instance of the robot with the specified trim values.
# Not shown are other optional parameters:
# - addr: The I2C address of the motor HAT, default is 0x60.
# - left_id: The ID of the left motor, default is 1.
# - right_id: The ID of the right motor, default is 2.
robot = Robot.Robot(left_trim=LEFT_TRIM, right_trim=RIGHT_TRIM)
# Now move the robot around!
# Each call below takes two parameters:
# - speed: The speed of the movement, a value from 0-255. The higher the value
# the faster the movement. You need to start with a value around 100
# to get enough torque to move the robot.
# - time (seconds): Amount of time to perform the movement. After moving for
# this amount of seconds the robot will stop. This parameter
# is optional and if not specified the robot will start moving
# forever.
robot.forward(150, 1.0) # Move forward at speed 150 for 1 second.
robot.left(200, 0.5) # Spin left at speed 200 for 0.5 seconds.
robot.forward(150, 1.0) # Repeat the same movement 3 times below...
robot.left(200, 0.5)
robot.forward(150, 1.0)
robot.left(200, 0.5)
robot.forward(150, 1.0)
robot.right(200, 0.5)
# Spin in place slowly for a few seconds.
robot.right(100) # No time is specified so the robot will start spinning forever.
time.sleep(2.0) # Pause for a few seconds while the robot spins (you could do
# other processing here though!).
robot.stop() # Stop the robot from moving.
# Now move backwards and spin right a few times.
robot.backward(150, 1.0)
robot.right(200, 0.5)
robot.backward(150, 1.0)
robot.right(200, 0.5)
robot.backward(150, 1.0)
robot.right(200, 0.5)
robot.backward(150, 1.0)
# That's it! Note that on exit the robot will automatically stop moving.

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setup.py
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@@ -3,7 +3,7 @@ use_setuptools()
from setuptools import setup, find_packages
setup(name = 'Adafruit_MotorHAT',
version = '1.2.0',
version = '1.3.0',
author = 'Limor Fried',
author_email = 'support@adafruit.com',
description = 'Library for Adafruit Motor HAT',