# validated: 2017-12-27 TW f9bece2ffbf7 edu/wpi/first/wpilibj/AnalogAccelerometer.java
#----------------------------------------------------------------------------
# Copyright (c) FIRST 2008-2017. All Rights Reserved.
# Open Source Software - may be modified and shared by FRC teams. The code
# must be accompanied by the FIRST BSD license file in the root directory of
# the project.
#----------------------------------------------------------------------------
import hal
from .analoginput import AnalogInput
from .interfaces import PIDSource
from .sensorbase import SensorBase
__all__ = ["AnalogAccelerometer"]
[docs]class AnalogAccelerometer(SensorBase):
"""Analog Accelerometer
The accelerometer reads acceleration directly through the sensor. Many
sensors have multiple axis and can be treated as multiple devices. Each
is calibrated by finding the center value over a period of time.
.. not_implemented: initAccelerometer
"""
PIDSourceType = PIDSource.PIDSourceType
def __init__(self, channel):
"""Constructor. Create a new instance of Accelerometer from either an existing
AnalogChannel or from an analog channel port index.
:param channel: port index or an already initialized AnalogInput
:type channel: int or :class:`.AnalogInput`
"""
super().__init__()
if not hasattr(channel, "getAverageVoltage"): # If 'channel' is an integer
self.analogChannel = AnalogInput(channel)
self.allocatedChannel = True
self.addChild(self.analogChannel)
else:
self.allocatedChannel = False
self.analogChannel = channel
self.voltsPerG = 1.0
self.zeroGVoltage = 2.5
self.pidSource = self.PIDSourceType.kDisplacement
hal.report(hal.UsageReporting.kResourceType_Accelerometer,
self.analogChannel.getChannel())
self.setName("Accelerometer", self.analogChannel.getChannel())
[docs] def free(self):
super().free()
if self.analogChannel and self.allocatedChannel:
self.analogChannel.free()
self.analogChannel = None
[docs] def getAcceleration(self):
"""Return the acceleration in Gs.
The acceleration is returned units of Gs.
:returns: The current acceleration of the sensor in Gs.
:rtype: float
"""
if not self.analogChannel:
return 0.0
return (self.analogChannel.getAverageVoltage() - self.zeroGVoltage) / self.voltsPerG
[docs] def setSensitivity(self, sensitivity):
"""Set the accelerometer sensitivity.
This sets the sensitivity of the accelerometer used for calculating
the acceleration. The sensitivity varies by accelerometer model.
There are constants defined for various models.
:param sensitivity: The sensitivity of accelerometer in Volts per G.
:type sensitivity: float
"""
self.voltsPerG = sensitivity
[docs] def setZero(self, zero):
"""Set the voltage that corresponds to 0 G.
The zero G voltage varies by accelerometer model. There are constants
defined for various models.
:param zero: The zero G voltage.
:type zero: float
"""
self.zeroGVoltage = zero
[docs] def setPIDSourceType(self, pidSource):
"""Set which parameter you are using as a process
control variable.
:param pidSource: An enum to select the parameter.
:type pidSource: :class:`.PIDSource.PIDSourceType`
"""
self.pidSource = pidSource
[docs] def getPIDSourceType(self):
return self.pidSource
[docs] def pidGet(self):
"""Get the Acceleration for the PID Source parent.
:returns: The current acceleration in Gs.
:rtype: float
"""
return self.getAcceleration()
[docs] def initSendable(self, builder):
builder.setSmartDashboardType("Accelerometer")
builder.addDoubleProperty("Value", self.getAcceleration, None)