User`s manual

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(www.EggtimerRocketry.com) for details. Similarly you can also use the nice little sounders sold
by Adept Rocketry, they make a very distinct sound that’s hard to miss even with other
background noise present.
ALED/BLED - Deployment Channel LEDs
ALED/BLED are designed to provide a visual indicator of deployment channel power and
igniter continuity. This lets you know immediately after connecting the igniter and powering up
the channel if something isn’t right. They use relatively little current, so leaving them on isn’t
likely to be a significant drain on your deployment battery.
The ALED/BLED outputs are current-limited with 820 ohm resistors, a 9v battery on the outputs
will source about 9ma of current to the LEDs. This is more than enough to brightly light up a
high-brightness T-1 sized LED. Note that these outputs are polarized, they are marked +/-, so
you need to make sure that you have these connected properly; the long lead of the LEDs goes to
the + output. If you’re using an LED that’s pre-wired in a holder, connect the red wire to the “+”
pad and the black wire to the “-“ pad.
Eggtimer Battery Options
The Eggtimer requires a battery with a nominal voltage of 3.0v-4.0v. The typical current draw is
about 8-10 ma when operating, and 2 ma when is Reset/Hold mode. This means that you have
several battery options:
· 3v Lithium batteries, such as a CR123 or CR2
· 3v Lithium “coin cells”, such as a CR2032, if they are used for a very short time
· 3v or 3.6v rechargeable Lithium batteries
· Two 1.5v alkaline batteries wired in series for 3v, typically size AAA or AA
· 3.6v rechargeable Nickel Metal Hydride (NiMh) battery packs
· 3.7v Lithium Ion (LiPo) cells
Because of the wide variety of rocket sizes and the different types of installations that are
possible, the Eggtimer does not come with a battery. There are a wide variety of battery options
available, which one you choose will depend on many factors:
1) The size of the rocket – Small rockets may require a smaller battery than a large rocket. If
you are trying to put the Eggtimer into the smallest possible space, a 3v Lithium “coin cell”
battery may work, but see the notes below.
2) How often you wish to replace the battery – Smaller lower-capacity batteries will have to be
replaced (or recharged) more often than larger batteries, which is the trade-off for the smaller
size