Archive for the ‘High Altitude’ Category

Busy day at the lab

Posted by JonM on 27 April 2008

We had a lot going on at the lab yesterday. In the early afternoon, Brian and Sirus continued hacking on the ground software, while 3ric, Leigh and I got the thermal chamber going again. We tested the BeeLine failsafe beacon, and it performed marvelously, showing only a very slight frequency drift (5kHz or so) down at -60C.

With a successful round of thermal testing under our belts, 3ric and Leigh then worked on getting our ground-station Internet gateways configured and running, and I worked on getting our new glider assembled.

Phil assembled a rig for thermal testing our glider flight controller and it's data acquisition, which involved some fairly intricate soldering:

As I was getting ready to pack it in for the night, there was continued thermal testing. Phil's thermal tests of the flight controller and data acquisition were quite successful, while Dan took a much more hands-on approach to thermal testing the science payload controllers:

All in all, a good day at the lab. It's good to see things coming together, and have everyone working so hard on getting things built and working together.

Belated software session writeup

Posted by DanHeidel on 16 April 2008

Lisa, 3ric, Brian, DavidL, Adam and myself got together to do some software hacking. To be more precise, everyone else did software hacking and I doodled on a legal pad, being sans laptop. Lisa worked on processing the 5-DOF intertial sensor. 3ric looked for a way to automate collection of VOR sites and DOS'ed everyone for a while. Adam worked on the RTOS. David worked on fixed point NMEA parsing code. I drafted up the processing internals for REHAB. Not sure what Brian did, Brian, care to chip in?

Here's my cellulose draft of the Nanocon network for REHAB. If I'm not feeling too lazy, I'll put some annotation on it.

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Avionics/Science meeting 04/14

Posted by DanHeidel on 15 April 2008

To celebrate tax day, we had the weekly avionics and science payload meeting. Me, Chicken and Phil were there, working on various odds and ends. I did some REHAB airframe work and tested it with a 2kg test load which it seemed to handle well. I shortened the main spar a few inches to reduce the bowing from the weight and it seems to dampen oscillations quite well. I also poked

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at some of the Sparkfun components that arrived. Phil and Chicken did... um I guess I forgot to ask what they were doing. Perhaps they can fill in the details.

As an aside, we really do need to get some more folks down to the lab for these meetings since we're going to have to start seriously fabbing stuff soon.

3ric and Amy stopped by briefly whereupon I was chastised for putting an insufficiently sexy photo in the HamSexy page of the wiki. If you go now, you can see that has been rectified.

Radio range testing

Posted by JonM on 12 April 2008

Dan and I went out today to do some radio range testing. We decided to start small and stay within Seattle city limits. We had two sets of sites, the first about four miles, from Magnolia Park to Alki Beach Park. I went up to Magnolia Park and set up a nice little testing station:

Test station at Alki

First and foremost was testing the Digi XTend RF modem, which will be our primary data link from the ground station to the payloads. Dan set one up on the Alki beach running medium power, and they immediately paired with a nice, strong, signal. Depending on the antenna orientation, we got from -62 dBm down to -74 dBm, which matches our calculations nicely. Further testing will be needed to verify the path fade, but I'm pretty sure we'll be able to get up to 100 miles of range with no problems.

The surprise star of the day was the BeeLine homing beacon. That little green guy was heard 4 miles away:

Pretty impressive for a self contained package that weighs less than half an ounce and
will run for 48 hours on a single charge!

After that success, we decamped and headed over to the second pair of test sites. I set up at the out of service boat ramp at Sand Point:

I got the call from Dan that we was set up and...nothing. It turns out that Dan had misinterpreted the south site (a boat ramp near Seward Park), and had setup in Seward Park proper. Our clear 8 mile line of site was now a clear 6 miles with 2 miles of Mercer Island in between. Ah well, at least the weather was nice.

Accel data

Posted by 3ricj on 10 April 2008

Using some nasty perl scripts and far too much headscratching, we got the following graph from a 7 story elevator ride. Units are in feet or Feet per second. w00t.


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