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The old headers were moved into folders because doing so avoids polluting the system include directories. Folder names were also normalized to lowercase.
229 lines
8.2 KiB
C++
229 lines
8.2 KiB
C++
/*----------------------------------------------------------------------------*/
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/* Copyright (c) 2008-2018 FIRST. All Rights Reserved. */
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/* Open Source Software - may be modified and shared by FRC teams. The code */
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/* must be accompanied by the FIRST BSD license file in the root directory of */
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/* the project. */
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/*----------------------------------------------------------------------------*/
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#pragma once
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#include <atomic>
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#include <memory>
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#include <thread>
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#include <vector>
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#include "frc/Counter.h"
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#include "frc/ErrorBase.h"
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#include "frc/PIDSource.h"
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#include "frc/smartdashboard/SendableBase.h"
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namespace frc {
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class DigitalInput;
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class DigitalOutput;
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/**
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* Ultrasonic rangefinder class.
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*
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* The Ultrasonic rangefinder measures absolute distance based on the round-trip
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* time of a ping generated by the controller. These sensors use two
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* transducers, a speaker and a microphone both tuned to the ultrasonic range. A
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* common ultrasonic sensor, the Daventech SRF04 requires a short pulse to be
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* generated on a digital channel. This causes the chirp to be emitted. A second
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* line becomes high as the ping is transmitted and goes low when the echo is
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* received. The time that the line is high determines the round trip distance
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* (time of flight).
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*/
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class Ultrasonic : public ErrorBase, public SendableBase, public PIDSource {
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public:
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enum DistanceUnit { kInches = 0, kMilliMeters = 1 };
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/**
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* Create an instance of the Ultrasonic Sensor.
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*
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* This is designed to support the Daventech SRF04 and Vex ultrasonic sensors.
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*
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* @param pingChannel The digital output channel that sends the pulse to
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* initiate the sensor sending the ping.
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* @param echoChannel The digital input channel that receives the echo. The
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* length of time that the echo is high represents the
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* round trip time of the ping, and the distance.
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* @param units The units returned in either kInches or kMilliMeters
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*/
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Ultrasonic(int pingChannel, int echoChannel, DistanceUnit units = kInches);
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/**
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* Create an instance of an Ultrasonic Sensor from a DigitalInput for the echo
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* channel and a DigitalOutput for the ping channel.
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*
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* @param pingChannel The digital output object that starts the sensor doing a
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* ping. Requires a 10uS pulse to start.
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* @param echoChannel The digital input object that times the return pulse to
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* determine the range.
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* @param units The units returned in either kInches or kMilliMeters
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*/
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Ultrasonic(DigitalOutput* pingChannel, DigitalInput* echoChannel,
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DistanceUnit units = kInches);
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/**
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* Create an instance of an Ultrasonic Sensor from a DigitalInput for the echo
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* channel and a DigitalOutput for the ping channel.
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*
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* @param pingChannel The digital output object that starts the sensor doing a
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* ping. Requires a 10uS pulse to start.
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* @param echoChannel The digital input object that times the return pulse to
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* determine the range.
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* @param units The units returned in either kInches or kMilliMeters
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*/
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Ultrasonic(DigitalOutput& pingChannel, DigitalInput& echoChannel,
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DistanceUnit units = kInches);
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/**
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* Create an instance of an Ultrasonic Sensor from a DigitalInput for the echo
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* channel and a DigitalOutput for the ping channel.
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*
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* @param pingChannel The digital output object that starts the sensor doing a
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* ping. Requires a 10uS pulse to start.
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* @param echoChannel The digital input object that times the return pulse to
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* determine the range.
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* @param units The units returned in either kInches or kMilliMeters
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*/
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Ultrasonic(std::shared_ptr<DigitalOutput> pingChannel,
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std::shared_ptr<DigitalInput> echoChannel,
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DistanceUnit units = kInches);
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~Ultrasonic() override;
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/**
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* Single ping to ultrasonic sensor.
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*
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* Send out a single ping to the ultrasonic sensor. This only works if
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* automatic (round robin) mode is disabled. A single ping is sent out, and
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* the counter should count the semi-period when it comes in. The counter is
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* reset to make the current value invalid.
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*/
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void Ping();
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/**
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* Check if there is a valid range measurement.
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*
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* The ranges are accumulated in a counter that will increment on each edge of
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* the echo (return) signal. If the count is not at least 2, then the range
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* has not yet been measured, and is invalid.
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*/
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bool IsRangeValid() const;
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/**
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* Turn Automatic mode on/off.
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*
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* When in Automatic mode, all sensors will fire in round robin, waiting a set
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* time between each sensor.
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*
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* @param enabling Set to true if round robin scheduling should start for all
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* the ultrasonic sensors. This scheduling method assures that
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* the sensors are non-interfering because no two sensors fire
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* at the same time. If another scheduling algorithm is
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* prefered, it can be implemented by pinging the sensors
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* manually and waiting for the results to come back.
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*/
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static void SetAutomaticMode(bool enabling);
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/**
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* Get the range in inches from the ultrasonic sensor.
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*
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* @return Range in inches of the target returned from the ultrasonic sensor.
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* If there is no valid value yet, i.e. at least one measurement
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* hasn't completed, then return 0.
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*/
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double GetRangeInches() const;
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/**
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* Get the range in millimeters from the ultrasonic sensor.
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*
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* @return Range in millimeters of the target returned by the ultrasonic
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* sensor. If there is no valid value yet, i.e. at least one
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* measurement hasn't completed, then return 0.
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*/
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double GetRangeMM() const;
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bool IsEnabled() const;
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void SetEnabled(bool enable);
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/**
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* Set the current DistanceUnit that should be used for the PIDSource base
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* object.
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*
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* @param units The DistanceUnit that should be used.
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*/
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void SetDistanceUnits(DistanceUnit units);
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/**
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* Get the current DistanceUnit that is used for the PIDSource base object.
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*
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* @return The type of DistanceUnit that is being used.
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*/
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DistanceUnit GetDistanceUnits() const;
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/**
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* Get the range in the current DistanceUnit for the PIDSource base object.
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*
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* @return The range in DistanceUnit
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*/
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double PIDGet() override;
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void SetPIDSourceType(PIDSourceType pidSource) override;
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void InitSendable(SendableBuilder& builder) override;
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private:
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/**
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* Initialize the Ultrasonic Sensor.
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*
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* This is the common code that initializes the ultrasonic sensor given that
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* there are two digital I/O channels allocated. If the system was running in
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* automatic mode (round robin) when the new sensor is added, it is stopped,
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* the sensor is added, then automatic mode is restored.
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*/
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void Initialize();
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/**
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* Background task that goes through the list of ultrasonic sensors and pings
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* each one in turn. The counter is configured to read the timing of the
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* returned echo pulse.
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*
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* DANGER WILL ROBINSON, DANGER WILL ROBINSON:
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* This code runs as a task and assumes that none of the ultrasonic sensors
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* will change while it's running. Make sure to disable automatic mode before
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* touching the list.
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*/
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static void UltrasonicChecker();
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// Time (sec) for the ping trigger pulse.
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static constexpr double kPingTime = 10 * 1e-6;
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// Priority that the ultrasonic round robin task runs.
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static constexpr int kPriority = 64;
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// Max time (ms) between readings.
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static constexpr double kMaxUltrasonicTime = 0.1;
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static constexpr double kSpeedOfSoundInchesPerSec = 1130.0 * 12.0;
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// Thread doing the round-robin automatic sensing
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static std::thread m_thread;
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// Ultrasonic sensors
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static std::vector<Ultrasonic*> m_sensors;
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// Automatic round-robin mode
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static std::atomic<bool> m_automaticEnabled;
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std::shared_ptr<DigitalOutput> m_pingChannel;
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std::shared_ptr<DigitalInput> m_echoChannel;
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bool m_enabled = false;
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Counter m_counter;
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DistanceUnit m_units;
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};
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} // namespace frc
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