User`s manual

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Also note that if you set the Airstart Delay too long (way too long...) and it expires AFTER
Nose-Over is detected, the CHB channel will not fire. This is a safety feature, so you don’t shoot
off the second stage while it’s pointing downward. If you are using the second stage’s motor for
drogue or main chute deployment, obviously those deployments aren’t going to happen; if you
are using the Eggtimer’s Main channel for deployment, it WILL fire, hopefully saving your
rocket so you can try it again later with more accurate settings.
Airstart firing altitude and time is recorded in Flight Summary memory as CHB, since CHB is
used for airstarts. Zeroes in these fields means that CHB didn’t fire, probably because either the
breakwire didn’t open up or your delay was too long and Nose-Over occurred first.
K Telemetry <0=Off, 1=On>
When set to “1”, flight time and altitude samples are sent through the serial port in real-time
during flights. Data streaming begins as soon as the pre-launch sampling begins, and continues
until the flight ends. Even if the memory runs out, the telemetry data will continue to stream
after landing is detected, it just won’t be saved to flight memory. If you’re using some kind of
RF telemetry package, this insures that you’re going to get a continuous data stream that you can
use to help find your rocket on the ground. We’ve all wandered around deserts, cow pastures, or
farm furrows for a few hours looking for a wayward rocket, so you can see the value in this!
Only two wires are required to send data to an external device, the GND and the TX lines. TX is
a TTL-compatible output (low < .8v, high > 2.4v) NOT an RS-232 output (low > 3v, high < -3v).
Data is streamed at 19,200 baud, so you will need to make sure that your radio device is
configured for that rate.
Note that many radio telemetry devices require a FCC Amateur Radio Novice license, so check
before you purchase anything. If you want to get into telemetry, you should probably go ahead
and get a Novice license anyway, you’ll need the knowledge to get your telemetry system
working and it’s pretty cheap… the exam fee is only $14 and the study guide is about $30.
Obviously, telemetry is a detailed subject in itself, so we will not cover it any further here.
O Comments
The Comments field is a 42-character free-form text field that you can use to identify you flight,
enter the data, rocket name, motor, etc. We recommend that you change it for every flight to
make it easier to identify the flights when you go to download them later. If you choose a pre-
programmed flight profile, it will be set to “Default Flight <n>”, where <n> is the flight profile
number from 1 to 8.
Note that if you abort a flight, for example you reset the processor after the Ready signal begins
to sound, all of the settings including the Comments will be carried over to the next flight. If you
want to change the Comments, you will need to go into the programming screen before the next
flight.