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Note: When you first get your Eggtimer, the flight memory is NOT initialized,
and it is NOT ready for flight! Please see Appendix A in the Eggtimer Users
Guide for instructions on how to clear the flight memory by performing a
Master Reset. You will need to do this before you can program or fly the
Eggtimer, or unpredictable results may follow!
About Wiring Your Eggtimer
The Eggtimer does not use screw terminal blocks to mount the wires, instead there are solder
pads to which you can solder #24 stranded wires. The wires in terminal blocks CAN work
loose with the forces of flight, so it's better to solder the wires on the board and to whatever
switches or battery clips you are using. If you are going to use removable connectors such as
for batteries, the connectors used for RC model servos (Deans, Futaba, Airtronics, etc.) work
very well; just buy a "servo extension" and you will get a 12" or longer pigtail with both a
male and female connector. We recommend against using slide switches for power, reset, etc.,
they have a tendency to "bounce" under high G forces, which is going to cause your Eggtimer
to lose power or reset and will ruin your whole day at the field. See the Eggtimer User's
Manual for some suggestions on switches, shunts, and jumpers.
Note that if you have installed the locking header kit, you will have to crimp the wires to the
pins. You need to use a "D-Sub" crimp tool, do NOT try to do it with pliers; you will not get a
good crimp and you will be frustrated because they'll just flatten out so they won't fit in the
socket. To terminate a wire in the pins, strip the wire clean, trim it down to about 1/16", insert
the wire into the pin so that the crimp on the back will crimp over the end of the insulation, and
crimp using the tool.
You will need to solder some wires to the Eggtimer board in order to test it, we like using the 4
stranded twisted-pair wiring that's used with Ethernet network cables. Get the cheapest ones
you can find (we've even seen them in dollar stores!), cut off the ends, and carefully strip about
1' of the jacket off at a time until you get the length you want. The nice thing about these
cables are that the wires are color-coded so it's going to make it easier to trace your wiring, and
the wires are twisted together so it's easier to route them. They are also in solid-striped pairs,
so it's easy to make sure that anything that's polarized (such as the battery connections) is
hooked up properly... by convention, solid goes to the "+" side, striped goes to the "-" side. If
you can find it, the "plenum rated" cable is the best... the jackets are heat-resistant Teflon ®
instead of the more common PVC. Note: we strongly recommend that you tin the wires
before soldering them to the Eggtimer board. This prevents loose strands of wires from
bridging the pads, or coming loose and lodging somewhere on the board (like underneath the
processor chip!). Trim the wires after soldering.
Testing your Eggtimer
You can test your Eggtimer very easily on your workbench, you do not need to install it into a
rocket first with a full-blown electronic deployment setup. All you need to do is to solder
some "pigtail" wires to the board, 12" is a good length. At a minimum, you will need to
connect the battery and short the switch wires together, but you can also test the deployment
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