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#include <Encoder.h>
#include <SampleRobot.h>
#include <SmartDashboard/SmartDashboard.h>
#include <Timer.h>
/**
* Sample program displaying the value of a quadrature encoder on the
* SmartDashboard.
* Quadrature Encoders are digital sensors which can detect the amount the
* encoder has rotated since starting as well as the direction in which the
* encoder shaft is rotating. However, encoders can not tell you the absolute
* position of the encoder shaft (ie, it considers where it starts to be the
* zero position, no matter where it starts), and so can only tell you how
* much the encoder has rotated since starting.
* Depending on the precision of an encoder, it will have fewer or greater
* ticks per revolution; the number of ticks per revolution will affect the
* conversion between ticks and distance, as specified by DistancePerPulse.
* One of the most common uses of encoders is in the drivetrain, so that the
* distance that the robot drives can be precisely controlled during the
* autonomous mode.
*/
class Robot: public frc::SampleRobot {
/**
* The Encoder object is constructed with 4 parameters, the last two being
* optional.
* The first two parameters (1, 2 in this case) refer to the ports on the
* roboRIO which the encoder uses. Because a quadrature encoder has
* two signal wires, the signal from two DIO ports on the roboRIO are used.
* The third (optional) parameter is a boolean which defaults to false.
* If you set this parameter to true, the direction of the encoder will
* be reversed, in case it makes more sense mechanically.
* The final (optional) parameter specifies encoding rate (k1X, k2X, or k4X)
* and defaults to k4X. Faster (k4X) encoding gives greater positional
* precision but more noise in the rate.
*/
frc::Encoder m_encoder { 1, 2, false, Encoder::k4X };
/**
* Time to wait between updating SmartDashboard values.
* It is generally a good idea to stick a short wait in these loops
* to avoid hogging CPU power, especially as there will be no
* perceivable difference in the SmartDashboard display.
*/
static constexpr double kUpdatePeriod = 0.005; // 5milliseconds / 0.005 seconds.
public:
Robot() {
/* Defines the number of samples to average when determining the rate.
* On a quadrature encoder, values range from 1-255; larger values
* result in smoother but potentially less accurate rates than lower
* values.
*/
m_encoder.SetSamplesToAverage(5);
/* Defines how far the mechanism attached to the encoder moves per pulse.
* In this case, we assume that a 360 count encoder is directly attached
* to a 3 inch diameter (1.5inch radius) wheel, and that we want to
* measure distance in inches.
*/
m_encoder.SetDistancePerPulse(1.0 / 360.0 * 2.0 * 3.1415 * 1.5);
/* Defines the lowest rate at which the encoder will not be considered
* stopped, for the purposes of the GetStopped() method.
* Units are in distance / second, where distance refers to the units
* of distance that you are using, in this case inches.
*/
m_encoder.SetMinRate(1.0);
}
/**
* Retrieve various information from the encoder and display it on the
* SmartDashboard.
*/
void OperatorControl() {
while (IsOperatorControl() && IsEnabled()) {
// Retrieve the net displacement of the Encoder since the lsat Reset.
frc::SmartDashboard::PutNumber("Encoder Distance",
m_encoder.GetDistance());
// Retrieve the current rate of the encoder.
frc::SmartDashboard::PutNumber("Encoder Rate", m_encoder.GetRate());
frc::Wait(kUpdatePeriod); // Wait a short bit before updating again.
}
}
};
START_ROBOT_CLASS(Robot)