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Fix #76, fix #79

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This finishes off implementing values and source for all (current)
classes in gpiozero. I'm afraid things get rather complex in this
commit. For starters, we've now got quite a few "aggregate" classes
which necessarily don't descend from GPIODevice. To implement values and
source on these I could either repeat a helluva lot of code or ... turn
to mixin classes. Yeah, it's multiple inheritance time, baby!

Unfortunately multiple inheritance doesn't work with __slots__ but we
really ought to keep functionality that they provide us (raise
AttributeError when an unknown attribute is set). So I've implemented
this with ... erm ... metaclasses. Sorry!
This commit is contained in:
Dave Jones
2015-10-19 13:36:31 +01:00
parent b0b54162cc
commit fa0a1b3cdd
5 changed files with 403 additions and 239 deletions
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104
gpiozero/input_devices.py
View File

@@ -1,4 +1,9 @@
from __future__ import division
from __future__ import (
unicode_literals,
print_function,
absolute_import,
division,
)
import inspect
import warnings
@@ -10,7 +15,13 @@ from RPi import GPIO
from w1thermsensor import W1ThermSensor
from spidev import SpiDev
from .devices import GPIODeviceError, GPIODeviceClosed, GPIODevice, GPIOQueue
from .devices import (
GPIODeviceError,
GPIODeviceClosed,
GPIODevice,
CompositeDevice,
GPIOQueue,
)
class InputDeviceError(GPIODeviceError):
@@ -35,13 +46,6 @@ class InputDevice(GPIODevice):
If `True`, the pin will be pulled high with an internal resistor. If
`False` (the default), the pin will be pulled low.
"""
__slots__ = (
'_pull_up',
'_active_edge',
'_inactive_edge',
)
def __init__(self, pin=None, pull_up=False):
if pin in (2, 3) and not pull_up:
raise InputDeviceError(
@@ -79,6 +83,10 @@ class InputDevice(GPIODevice):
@property
def pull_up(self):
"""
If `True`, the device uses a pull-up resistor to set the GPIO pin
"high" by default. Defaults to `False`.
"""
return self._pull_up
def __repr__(self):
@@ -102,15 +110,6 @@ class WaitableInputDevice(InputDevice):
Note that this class provides no means of actually firing its events; it's
effectively an abstract base class.
"""
__slots__ = (
'_active_event',
'_inactive_event',
'_when_activated',
'_when_deactivated',
'_last_state',
)
def __init__(self, pin=None, pull_up=False):
super(WaitableInputDevice, self).__init__(pin, pull_up)
self._active_event = Event()
@@ -121,7 +120,7 @@ class WaitableInputDevice(InputDevice):
def wait_for_active(self, timeout=None):
"""
Halt the program until the device is activated, or the timeout is
Pause the script until the device is activated, or the timeout is
reached.
timeout: `None`
@@ -132,7 +131,7 @@ class WaitableInputDevice(InputDevice):
def wait_for_inactive(self, timeout=None):
"""
Halt the program until the device is deactivated, or the timeout is
Pause the script until the device is deactivated, or the timeout is
reached.
timeout: `None`
@@ -248,9 +247,6 @@ class DigitalInputDevice(WaitableInputDevice):
ignore changes in state after an initial change. This defaults to
`None` which indicates that no bounce compensation will be performed.
"""
__slots__ = ()
def __init__(self, pin=None, pull_up=False, bounce_time=None):
super(DigitalInputDevice, self).__init__(pin, pull_up)
try:
@@ -301,9 +297,6 @@ class SmoothedInputDevice(WaitableInputDevice):
If `True`, a value will be returned immediately, but be aware that this
value is likely to fluctuate excessively.
"""
__slots__ = ('_queue', '_threshold', '__weakref__')
def __init__(
self, pin=None, pull_up=False, threshold=0.5,
queue_len=5, sample_wait=0.0, partial=False):
@@ -388,6 +381,9 @@ class SmoothedInputDevice(WaitableInputDevice):
@property
def is_active(self):
"""
Returns `True` if the device is currently active and `False` otherwise.
"""
return self.value > self.threshold
@@ -399,9 +395,6 @@ class Button(DigitalInputDevice):
side of the switch, and ground to the other (the default `pull_up` value
is `True`).
"""
__slots__ = ()
def __init__(self, pin=None, pull_up=True, bouncetime=None):
super(Button, self).__init__(pin, pull_up, bouncetime)
@@ -426,9 +419,6 @@ class MotionSensor(SmoothedInputDevice):
particularly "jittery" you may wish to set this to a higher value (e.g. 5)
to mitigate this.
"""
__slots__ = ()
def __init__(
self, pin=None, queue_len=1, sample_rate=10, threshold=0.5,
partial=False):
@@ -458,12 +448,6 @@ class LightSensor(SmoothedInputDevice):
class repeatedly discharges the capacitor, then times the duration it takes
to charge (which will vary according to the light falling on the LDR).
"""
__slots__ = (
'_charge_time_limit',
'_charged',
)
def __init__(
self, pin=None, queue_len=5, charge_time_limit=0.01,
threshold=0.1, partial=False):
@@ -517,17 +501,11 @@ class TemperatureSensor(W1ThermSensor):
return self.get_temperature()
class AnalogInputDevice(object):
class AnalogInputDevice(CompositeDevice):
"""
Represents an analog input device connected to SPI (serial interface).
"""
__slots__ = (
'_device',
'_bits',
'_spi',
)
def __init__(self, device=0, bits=None):
if bits is None:
raise InputDeviceError('you must specify the bit resolution of the device')
@@ -537,25 +515,32 @@ class AnalogInputDevice(object):
self._bits = bits
self._spi = SpiDev()
self._spi.open(0, self.device)
super(AnalogInputDevice, self).__init__()
def close(self):
"""
Shut down the device and release all associated resources.
"""
if self._spi:
s = self._spi
self._spi = None
s.close()
def __enter__(self):
return self
def __exit__(self, exc_type, exc_value, exc_tb):
self.close()
super(AnalogInputDevice, self).close()
@property
def bus(self):
"""
The SPI bus that the device is connected to. As the Pi only has a
single (user accessible) SPI bus, this always returns 0.
"""
return 0
@property
def device(self):
"""
The select pin that the device is connected to. The Pi has two select
pins so this will be 0 or 1.
"""
return self._device
def _read(self):
@@ -563,13 +548,15 @@ class AnalogInputDevice(object):
@property
def value(self):
"""
A value read from the device. This will be a floating point value
between 0 and 1 (scaled according to the number of bits supported by
the device).
"""
return self._read() / (2**self._bits - 1)
class MCP3008(AnalogInputDevice):
__slots__ = ('_channel')
def __init__(self, device=0, channel=0):
if not 0 <= channel < 8:
raise InputDeviceError('channel must be between 0 and 7')
@@ -578,6 +565,10 @@ class MCP3008(AnalogInputDevice):
@property
def channel(self):
"""
The channel to read data from. The MCP3008 has 8 channels (so this will
be between 0 and 7) while the MCP3004 has 4 channels (range 0 to 3).
"""
return self._channel
def _read(self):
@@ -602,11 +593,10 @@ class MCP3008(AnalogInputDevice):
class MCP3004(MCP3008):
__slots__ = ()
def __init__(self, device=0, channel=0):
# MCP3004 protocol is identical to MCP3008 but the top bit of the
# channel number must be 0 (effectively restricting it to 4 channels)
if not 0 <= channel < 4:
raise InputDeviceError('channel must be between 0 and 3')
super(MCP3004, self).__init__(device, channel)