2 Vertical Acceleration:: Select a value, and then choose whether
3 acceleration away from the ground should be above or below that
4 value. Acceleration is positive upwards, so accelerating towards the
5 ground would produce negative numbers. Acceleration during descent is
6 noisy and inaccurate, so be careful when using it during these phases
9 Ascent rate:: Select a value, and then choose whether ascent rate
10 should be above or below that value. Ascent rate is positive upwards,
11 so moving towards the ground would produce negative numbers. Ascent
12 rate during descent is a bit noisy and so be careful when using it
13 during these phases of the flight.
15 Height above pad:: Select a value, and then choose whether the height
16 above the launch pad should be above or below that value. Note that
17 because EasyTimer has only a low-range accelerometer and no barometer,
18 this value will not be very reliable on that device.
20 Orientation:: TeleMega, EasyMega and EasyTimer contain a 3-axis
21 gyroscope and accelerometer which is used to compute the orientation
22 of the rocket. A record of orientations over the last 0.64 seconds is
23 kept and the largest value within this period is compared with the
24 specified value. Note that the tilt angle is not the change in angle
25 from the launch pad, but rather absolute relative to gravity—the
26 3-axis accelerometer is used to compute the angle of the rocket on the
27 launch pad and initialize the system.
31 Because this value is computed by integrating
32 rate gyros, it gets progressively less
33 accurate as the flight goes on. It should have
34 an accumulated error of less than 0.2°/second
35 (after 10 seconds of flight, the error should
38 The usual use of the orientation configuration
39 is to ensure that the rocket is traveling
40 mostly upwards when deciding whether to ignite
41 air starts or additional stages. For that,
42 choose a reasonable maximum angle (like 20°)
43 and set the motor igniter to require an angle
44 of less than that value.
47 Flight Time:: Time since launch. Select a value and choose whether to
48 activate the pyro channel before or after that amount of time.
51 Firmware versions older than 1.8.6 have a bug which resets the time
52 since launch to zero each time a motor starts burning. Update firmware
53 to get the correct behavior.
56 Firmware versions older than 1.9.8 cannot use times longer
57 than 327.67 seconds. Update firmware if you need a longer time.
59 Ascending:: A deprecated configuration value which was the same as
60 setting Ascent rate > 0. Existing configurations using this will be
61 cleared and must be reconfigured by the user.
63 Descending:: A deprecated configuration value which was the same as
64 setting Ascent rate < 0. Existing configurations using this will be
65 cleared and must be reconfigured by the user.
67 After Motor:: The flight software counts each time the rocket starts
68 accelerating and then decelerating (presumably due to a motor or
69 motors burning). Use this value for multi-staged or multi-airstart
70 launches. As of version 1.8.6 firmware, this checks to make sure at
71 least this many motors have burned. Before version 1.8.6, this checked
72 to make sure that exactly this many motors had burned.
74 Delay:: Once the other parameters all become true, a timer is
75 started for the specified amount of time. While the timer is running,
76 the other parameters are checked repeatedly and if any of them become
77 false, then the pyro channel is disabled and will not fire. If the
78 timer expires and all of the other parameters have remained true for
79 the entire time, then the pyro channel is fired.
82 Firmware versions older than 1.9.8 cannot use delays longer
83 than 327.67 seconds. Update firmware if you need a longer delay.
85 Flight State:: The flight software tracks the flight
86 through a sequence of states:
88 * Boost. The motor has lit and the rocket is
89 accelerating upwards. Ascent rate will be greater than zero.
90 Vertical acceleration will be greater than zero.
92 * Fast. The motor has burned out and the
93 rocket is decelerating, but it is going
94 faster than 200m/s. Ascent rate will be greater than zero. Vertical
95 acceleration will be less than zero.
97 * Coast. The rocket is still moving upwards
98 and decelerating, but the Ascent rate is less
99 than 200m/s. Ascent rate will greater than zero. Vertical
100 acceleration will be less than zero.
102 * Drogue. The rocket has reached apogee and is heading back down, but
103 is above the configured Main altitude. Ascent rate will be less
104 than zero during this state. Vertical acceleration will be negative
105 until the rocket reaches a terminal descent rate, at which point
106 Vertical acceleration will be zero. Both Ascent rate and Vertical
107 acceleration are very noisy in this state, so be careful when
108 trying to use them to control pyro channels. This state selection
109 is not available on EasyTimer.
111 * Main. The rocket is still descending, and
112 is below the Main altitude. Ascent rate will be less than zero
113 during this state. Vertical acceleration may be briefly less than
114 zero as the rocket slows from drogue descent to main descent, but
115 it will settle down to a zero value once the rocket has reached the
116 terminal velocity under the main chute. Ascent rate and Vertical
117 acceleration should be much less noisy once the main chute has
118 deployed. This state selection is not available on EasyTimer.
120 * Landed. The rocket is no longer moving.
122 You can select a state to limit when the pyro channel may activate;
123 note that the check is based on when the rocket transitions *into* the
124 state, and so checking for “greater than Boost” means that the rocket
125 is currently in boost or some later state.
127 When a motor burns out, the rocket enters either Fast or Coast state
128 (depending on how fast it is moving). If the computer detects upwards
129 acceleration again, it will move back to Boost state.
projects / fw / altos / blob