Eggtimer Rocketry Eggtimer User Manual page 30

The beep codes are:
Number of
Beeps
1
2
3
4
5
Note that if you are using a servo for deployment, you MUST connect a 39 ohm 1/4W resistor across
the deployment channel's output terminals in addition to connecting the servo's control input to the
"+" deployment channel output and the servo's power leads to the deployment battery. If you do
not hook up the resistor, there will be no continuity detected across the output channel leads, AND
the servo's control input has no way of being pulled to ground so it will not work.
Important: The self-test routine is executed ONCE when the Eggtimer is powered on. In the event
that it passes self-test and a condition arises after it has passed, it will NOT notify you of this fact.
In particular, if you turn off the deployment power after the Eggtimer has gone into the Ready for
Flight mode, the Eggtimer will continue to report that it is Ready. We have provided deployment
continuity LED outputs for this reason, so you can get a quick visual check of your deployment
channels' status. If for some reason you need to disconnect the deployment power, we STRONGLY
recommend that you also Reset or power off the Eggtimer, so that you do not end up launching with
the deployment power off.
OK, we're ready, so press the button already! ☺
In the Air...
Once your rocket is launched, altitude samples are taken at a rate determined by the Ascent Samples
setting. These setting are saved into a special rotating pool of memory until the LDA altitude is
reached, then they begin to be saved into the "regular" memory. When your rocket reaches LDA,
the burn timer starts and velocity profile data begins to be computed.
Velocity readings are computed based on the difference in altitude between successive samples and
the elapsed time between the samples. In a perfect world, this would give you a precise and 100%
accurate velocity reading. The reality is somewhat different, however. There are several things that
can introduce errors into the velocity reading: angle of attack, wind, errors in the pressure readings
due to aerodynamic influences, and time differences. If you measure the launch angle prior to
launch, you can calculate this error, although anything (such as wind) what makes the rocket deviate
from a straight-line path will pretty much negate this compensation unless you had set the angle to a
really high value (over 15°). If the pressure ports in your payload bay aren't sized properly, this
Problem
Battery Low ( < 2.8v)
Altimeter Sensor or Hardware Error
Breakwire open (airstarts only)
Channel A (Main) error - igniter/servo/battery
Channel B (Drogue/Airstart) error – igniter/servo/battery
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