Hi David,

The shore power connector on the rocket connects has three purposes:

1. It conveys power ("shore power") to the rocket to charge the
batteries and run the avionics system during testing or before launch.
Shore power either comes from a power brick plugged into the wall, or it
comes from a 12V to 20V DC-DC converter that runs off of the launch
tower computer's solar-recharged lead-acid battery pack. You can see the
solar panel, batteries, and launch tower computer here:

http://psas.pdx.edu/Lv2LaunchTowerElectronics/ag_lt_ltc.jpg

2. It allows us to talk directly to the APS microcontroller using a
three wire UART (TX, RX, GND).

3. It acts as one of many launch detect sensors: when we're armed for
flight, and the launch tower computer fires the igniter, then the shore
power connector being yanked out pretty much means you've launched. Of
course it's never that simple, because the cord could fall off by
accident, or the connector could get jammed, etc. We have a fancy lever
mechanism for pulling the plug out of the socket on launch; when we
break out the launch tower computer this spring for testing, we'll show
that off.

The connector we're thinking about using is a high reliability medical
connector that has just the right properties: it's keyed, it slides out
easily, it doesn't jam, and it has high current capabilities. I don't
have the part number right now, but eventually we'll post it to the web.
Right now we're thinking of a seven pin connector:

2x V+
2x GND
1x TX
1x RX
1x Launch detect (shorted to ground)

We'll have a short "on the bench" cable for testing, and we'll have a
very long (~ 20 ft) cable that goes from the LTC to the rocket for the
actual launch.

Andrew

da...@cecs.pdx.edu wrote:
> hey,
> doing some research on the charger, and am curious as to what type of
> external connection we will have, are we simply plugging into an outlet,
> or are we dealing with a cable of some sort?
> 
> David

-- 
-------------------------------------------------------
Andrew Greenberg

Portland State Aerospace Society (http://psas.pdx.edu/)
and...@psas.pdx.edu  P: 503.788.1343  C: 503.708.7711
-------------------------------------------------------

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