LED flashes once per high beep and the red LED flashes once per low beep. The order
of the channel beeps is the same as the order of the channel outputs along the terminal
block. First is the Apogee channel, then main, then 3
rd
, then 4
th
. In prelaunch mode, the
blue LED will flash once per second, and the red light will flash during beeps. The
button, located on the terminal block side of the board, can be used to switch between
wait and prelaunch modes.
The diagram (right) shows the
different operating modes of the
Raven and the transitions from
one mode to another.
Caution: If electronic deployments are expected, do not launch unless the Raven is
beeping with the expected number of connected output charges.
Liftoff Detection and flight
In prelaunch mode, the Raven is watching the axial accelerometer to detect liftoff. Any
readings less than 3.0 Gs are ignored. The Raven is also updating the accelerometer
calibration offset it uses during the flight, to maximize the accuracy of its apogee
detection. If the rocket is dropped a short distance, the Raven will ignore the subsequent
contact to avoid premature liftoff detection.
Despite these features, it is possible for the Raven to misinterpret normal handling as
a liftoff, so do not arm and/or turn on the Raven with charges connected until the
rocket is installed in the launch rail or tower and the rocket is pointed in a safe
direction.
The Raven will detect liftoff when accelerometer readings in excess of 3 Gs add up to a 3
mph upward velocity. Upon detection of liftoff, a prelaunch data buffer of 0.352 to 0.704
seconds will be stored into flash memory, and data recording continues from there.
In liftoff mode, the Raven’s red LED lights continuously, and the following data is
stored:
Periodic measurements:
400 Hz axial Accelerometer, +/- 105 Gs
200 Hz lateral Accelerometer, +/- 105 Gs
20 Hz Baro data, +/- 0.3% accuracy
20 Hz voltage on each of 4 outputs
40 Hz output current
20 Hz high-precision temperature sensor
20 Hz for all flight events used for deployment logic.
Once per flight:
Flight counter
All output program settings
Wait
(blue flash)
Landed
(red flash)
Pre-Launch
(red blue flash)
Liftoff
(Solid Red)
button
button
Accel > 3.0 Gs &
Velocity > 3 ft/sec
Baro steady
Power
Up
