130 lines
5.8 KiB
HTML
130 lines
5.8 KiB
HTML
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Vertical Acceleration:: Select a value, and then choose whether
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acceleration away from the ground should be above or below that
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value. Acceleration is positive upwards, so accelerating towards the
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ground would produce negative numbers. Acceleration during descent is
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noisy and inaccurate, so be careful when using it during these phases
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of the flight.
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Ascent rate:: Select a value, and then choose whether ascent rate
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should be above or below that value. Ascent rate is positive upwards,
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so moving towards the ground would produce negative numbers. Ascent
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rate during descent is a bit noisy and so be careful when using it
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during these phases of the flight.
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Height above pad:: Select a value, and then choose whether the height
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above the launch pad should be above or below that value. Note that
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because EasyTimer has only a low-range accelerometer and no barometer,
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this value will not be very reliable on that device.
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Orientation:: TeleMega, EasyMega and EasyTimer contain a 3-axis
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gyroscope and accelerometer which is used to compute the orientation
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of the rocket. A record of orientations over the last 0.64 seconds is
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kept and the largest value within this period is compared with the
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specified value. Note that the tilt angle is not the change in angle
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from the launch pad, but rather absolute relative to gravity—the
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3-axis accelerometer is used to compute the angle of the rocket on the
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launch pad and initialize the system.
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[NOTE]
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====
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Because this value is computed by integrating
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rate gyros, it gets progressively less
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accurate as the flight goes on. It should have
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an accumulated error of less than 0.2°/second
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(after 10 seconds of flight, the error should
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be less than 2°).
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The usual use of the orientation configuration
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is to ensure that the rocket is traveling
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mostly upwards when deciding whether to ignite
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air starts or additional stages. For that,
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choose a reasonable maximum angle (like 20°)
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and set the motor igniter to require an angle
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of less than that value.
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====
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Flight Time:: Time since launch. Select a value and choose whether to
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activate the pyro channel before or after that amount of time.
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[WARNING]
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Firmware versions older than 1.8.6 have a bug which resets the time
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since launch to zero each time a motor starts burning. Update firmware
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to get the correct behavior.
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[WARNING]
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Firmware versions older than 1.9.8 cannot use times longer
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than 327.67 seconds. Update firmware if you need a longer time.
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Ascending:: A deprecated configuration value which was the same as
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setting Ascent rate > 0. Existing configurations using this will be
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cleared and must be reconfigured by the user.
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Descending:: A deprecated configuration value which was the same as
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setting Ascent rate < 0. Existing configurations using this will be
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cleared and must be reconfigured by the user.
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After Motor:: The flight software counts each time the rocket starts
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accelerating and then decelerating (presumably due to a motor or
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motors burning). Use this value for multi-staged or multi-airstart
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launches. As of version 1.8.6 firmware, this checks to make sure at
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least this many motors have burned. Before version 1.8.6, this checked
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to make sure that exactly this many motors had burned.
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Delay:: Once the other parameters all become true, a timer is
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started for the specified amount of time. While the timer is running,
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the other parameters are checked repeatedly and if any of them become
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false, then the pyro channel is disabled and will not fire. If the
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timer expires and all of the other parameters have remained true for
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the entire time, then the pyro channel is fired.
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[WARNING]
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Firmware versions older than 1.9.8 cannot use delays longer
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than 327.67 seconds. Update firmware if you need a longer delay.
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Flight State:: The flight software tracks the flight
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through a sequence of states:
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* Boost. The motor has lit and the rocket is
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accelerating upwards. Ascent rate will be greater than zero.
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Vertical acceleration will be greater than zero.
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* Fast. The motor has burned out and the
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rocket is decelerating, but it is going
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faster than 200m/s. Ascent rate will be greater than zero. Vertical
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acceleration will be less than zero.
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* Coast. The rocket is still moving upwards
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and decelerating, but the Ascent rate is less
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than 200m/s. Ascent rate will greater than zero. Vertical
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acceleration will be less than zero.
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* Drogue. The rocket has reached apogee and is heading back down, but
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is above the configured Main altitude. Ascent rate will be less
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than zero during this state. Vertical acceleration will be negative
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until the rocket reaches a terminal descent rate, at which point
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Vertical acceleration will be zero. Both Ascent rate and Vertical
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acceleration are very noisy in this state, so be careful when
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trying to use them to control pyro channels. This state selection
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is not available on EasyTimer.
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* Main. The rocket is still descending, and
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is below the Main altitude. Ascent rate will be less than zero
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during this state. Vertical acceleration may be briefly less than
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zero as the rocket slows from drogue descent to main descent, but
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it will settle down to a zero value once the rocket has reached the
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terminal velocity under the main chute. Ascent rate and Vertical
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acceleration should be much less noisy once the main chute has
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deployed. This state selection is not available on EasyTimer.
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* Landed. The rocket is no longer moving.
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You can select a state to limit when the pyro channel may activate;
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note that the check is based on when the rocket transitions *into* the
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state, and so checking for “greater than Boost” means that the rocket
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is currently in boost or some later state.
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When a motor burns out, the rocket enters either Fast or Coast state
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(depending on how fast it is moving). If the computer detects upwards
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acceleration again, it will move back to Boost state.
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