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Merge pull request google#90 from google/aiy_common
Add AIY common drivers.
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| # Copyright 2017 Google Inc. | ||
| # | ||
| # Licensed under the Apache License, Version 2.0 (the "License"); | ||
| # you may not use this file except in compliance with the License. | ||
| # You may obtain a copy of the License at | ||
| # | ||
| # http://www.apache.org/licenses/LICENSE-2.0 | ||
| # | ||
| # Unless required by applicable law or agreed to in writing, software | ||
| # distributed under the License is distributed on an "AS IS" BASIS, | ||
| # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | ||
| # See the License for the specific language governing permissions and | ||
| # limitations under the License. | ||
| """This library provides common drivers for the AIY projects.""" | ||
|
|
||
| import itertools | ||
| import os | ||
| import threading | ||
| import time | ||
|
|
||
| import RPi.GPIO as GPIO | ||
|
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|
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| class Button(object): | ||
| """Detect edges on the given GPIO channel.""" | ||
|
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||
| def __init__(self, | ||
| channel, | ||
| polarity=GPIO.FALLING, | ||
| pull_up_down=GPIO.PUD_UP, | ||
| debounce_time=0.15): | ||
| """A simple GPIO-based button driver. | ||
| This driver supports a simple GPIO-based button. It works by detecting | ||
| edges on the given GPIO channel. Debouncing is automatic. | ||
| Args: | ||
| channel: the GPIO pin number to use (BCM mode) | ||
| polarity: the GPIO polarity to detect; either GPIO.FALLING or | ||
| GPIO.RISING. | ||
| pull_up_down: whether the port should be pulled up or down; defaults to | ||
| GPIO.PUD_UP. | ||
| debounce_time: the time used in debouncing the button in seconds. | ||
| """ | ||
|
|
||
| if polarity not in [GPIO.FALLING, GPIO.RISING]: | ||
| raise ValueError( | ||
| 'polarity must be one of: GPIO.FALLING or GPIO.RISING') | ||
|
|
||
| self.channel = int(channel) | ||
| self.polarity = polarity | ||
| self.expected_value = polarity == GPIO.RISING | ||
| self.debounce_time = debounce_time | ||
|
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| GPIO.setmode(GPIO.BCM) | ||
| GPIO.setup(channel, GPIO.IN, pull_up_down=pull_up_down) | ||
|
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| self.callback = None | ||
|
|
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| def wait_for_press(self): | ||
| """Waits for the button to be pressed. | ||
| This method blocks until the button is pressed. | ||
| """ | ||
| GPIO.add_event_detect(self.channel, self.polarity) | ||
| while True: | ||
| if GPIO.event_detected(self.channel) and self._debounce(): | ||
| GPIO.remove_event_detect(self.channel) | ||
| return | ||
| else: | ||
| time.sleep(0.1) | ||
|
|
||
| def on_press(self, callback): | ||
| """Calls the callback whenever the button is pressed. | ||
| Args: | ||
| callback: a function to call whenever the button is pressed. It should | ||
| take a single channel number. | ||
| Example: | ||
| def MyButtonPressHandler(channel): | ||
| print "button pressed: channel = %d" % channel | ||
| my_button.on_press(MyButtonPressHandler) | ||
| """ | ||
| GPIO.remove_event_detect(self.channel) | ||
| self.callback = callback | ||
| GPIO.add_event_detect( | ||
| self.channel, self.polarity, callback=self._debounce_and_callback) | ||
|
|
||
| def _debounce_and_callback(self, _): | ||
| if self._debounce(): | ||
| self.callback() | ||
|
|
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| def _debounce(self): | ||
| """Debounces the GPIO signal. | ||
| Check that the input holds the expected value for the debounce | ||
| period, to avoid false trigger on short pulses. | ||
| """ | ||
| start = time.time() | ||
| while time.time() < start + self.debounce_time: | ||
| if GPIO.input(self.channel) != self.expected_value: | ||
| return False | ||
| time.sleep(0.01) | ||
| return True | ||
|
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||
|
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||
| class LED: | ||
| """Starts a background thread to show patterns with the LED. | ||
| Simple usage: | ||
| my_led = LED(channel = 25) | ||
| my_led.start() | ||
| my_led.set_state(LED_BEACON) | ||
| my_led.stop() | ||
| """ | ||
|
|
||
| LED_OFF = 0 | ||
| LED_ON = 1 | ||
| LED_BLINK = 2 | ||
| LED_BLINK_3 = 3 | ||
| LED_BEACON = 4 | ||
| LED_BEACON_DARK = 5 | ||
| LED_DECAY = 6 | ||
| LED_PULSE_SLOW = 7 | ||
| LED_PULSE_QUICK = 8 | ||
|
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||
| def __init__(self, channel): | ||
| self.animator = threading.Thread(target=self._animate) | ||
| self.channel = channel | ||
| self.iterator = None | ||
| self.running = False | ||
| self.state = None | ||
| self.sleep = 0 | ||
|
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||
| GPIO.setmode(GPIO.BCM) | ||
| GPIO.setup(channel, GPIO.OUT) | ||
| self.pwm = GPIO.PWM(channel, 100) | ||
|
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| self.lock = threading.Lock() | ||
|
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| def start(self): | ||
| """Starts the LED driver.""" | ||
| with self.lock: | ||
| if not self.running: | ||
| self.running = True | ||
| self.pwm.start(0) # off by default | ||
| self.animator.start() | ||
|
|
||
| def stop(self): | ||
| """Stops the LED driver and sets the LED to off.""" | ||
| with self.lock: | ||
| if self.running: | ||
| self.running = False | ||
| self.animator.join() | ||
| self.pwm.stop() | ||
|
|
||
| def set_state(self, state): | ||
| """Sets the LED driver's new state. | ||
| Note the LED driver must be started for this to have any effect. | ||
| """ | ||
| with self.lock: | ||
| self.state = state | ||
|
|
||
| def _animate(self): | ||
| while True: | ||
| state = None | ||
| running = False | ||
| with self.lock: | ||
| state = self.state | ||
| self.state = None | ||
| running = self.running | ||
| if not running: | ||
| return | ||
| if state: | ||
| if not self._parse_state(state): | ||
| raise ValueError('unsupported state: %d' % state) | ||
| if self.iterator: | ||
| self.pwm.ChangeDutyCycle(next(self.iterator)) | ||
| time.sleep(self.sleep) | ||
| else: | ||
| # We can also wait for a state change here with a Condition. | ||
| time.sleep(1) | ||
|
|
||
| def _parse_state(self, state): | ||
| self.iterator = None | ||
| self.sleep = 0.0 | ||
| if state == self.LED_OFF: | ||
| self.pwm.ChangeDutyCycle(0) | ||
| return True | ||
| if state == self.LED_ON: | ||
| self.pwm.ChangeDutyCycle(100) | ||
| return True | ||
| if state == self.LED_BLINK: | ||
| self.iterator = itertools.cycle([0, 100]) | ||
| self.sleep = 0.5 | ||
| return True | ||
| if state == self.LED_BLINK_3: | ||
| self.iterator = itertools.cycle([0, 100] * 3 + [0, 0]) | ||
| self.sleep = 0.25 | ||
| return True | ||
| if state == self.LED_BEACON: | ||
| self.iterator = itertools.cycle( | ||
| itertools.chain([30] * 100, [100] * 8, range(100, 30, -5))) | ||
| self.sleep = 0.05 | ||
| return True | ||
| if state == self.LED_BEACON_DARK: | ||
| self.iterator = itertools.cycle( | ||
| itertools.chain([0] * 100, range(0, 30, 3), range(30, 0, -3))) | ||
| self.sleep = 0.05 | ||
| return True | ||
| if state == self.LED_DECAY: | ||
| self.iterator = itertools.cycle(range(100, 0, -2)) | ||
| self.sleep = 0.05 | ||
| return True | ||
| if state == self.LED_PULSE_SLOW: | ||
| self.iterator = itertools.cycle( | ||
| itertools.chain(range(0, 100, 2), range(100, 0, -2))) | ||
| self.sleep = 0.1 | ||
| return True | ||
| if state == self.LED_PULSE_QUICK: | ||
| self.iterator = itertools.cycle( | ||
| itertools.chain(range(0, 100, 5), range(100, 0, -5))) | ||
| self.sleep = 0.05 | ||
| return True | ||
| return False |
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