Appendix A – Typical Connections
Below is a picture from a test setup that we have for the Eggtimer. It is very typical of what
you would use in a multiple-deployment rocket… a 3.7V LiPo battery for the Eggtimer’s
computer, and a 9V battery for the deployment channels. You can see that the 9V battery is
connected to both of the deployment channels’ battery pads (BCHA, BCHB). We are using
miniature Christmas tree lights for the igniter test load, they work very well and are cheap. We
have hooked up all three external LEDs (READY, ALED, and BLED), an external pizo buzzer
(BUZ), and a switch on the SW terminals. (It’s a cheap slide switch, we recommend that you
do not fly one of these, get a Schurter 033.4501 rotary switch instead). Note that this example
is actually a RevC board, but the connections are virtually the same on the RevD board as well.
We have also connected a pigtail to the RST line. In a real flight, you can twist these together
and have them outside the rocket; to start the flight sequence, you simply take them apart and
tape them up so they won’t short during the flight. We have not connected the Breakwire
(BW) terminals, they are used only for airstart flights; that subject is covered extensively in the
Eggtimer Users Guide.
