Initial Commit - Copy from Altus Metrum AltOS

doc/pyro-channels.inc

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