The winds are getting better...finally

I've been running the Balloon Track program a few times a month since mid-November and this week is the first time I've seen a projected landing site that isn't in the Atlantic :) Balloon Track is still showing an estimated launch-to-landing distance of 142 miles though. That seems like a long way to try to keep up with a balloon when driving on random roads and through lots of small towns. Maybe our balloon will be very cooperative and stay directly over I-40 the whole way :) If this ends up being as good as the winds get then we'll have to think about having a launch crew in Asheboro and a chase crew somewhere East of I-95.

We'll keep checking the projected flight path and hopefully we'll be able to do a launch sometime in April or May.

Stay tuned for further developments...

Having caught up on my blog reading, I realized that we haven't posted in a month. Just wanted to give any readers of this blog a heads-up that we *probably* won't be launching in the near future. I haven't run any of the weather models myself (Daniel's been doing that, while I've been working on some basic air-density models and temperature measurement devices), but the winter winds in NC are likely to carry our balloon far out to sea.

On the temperature front, I ordered some iButtons to log the temperature and humidity of the balloon box, just because we can. I ordered the Thermochron (tempearture only) and Hygrochron (temperature and relative humidity) from iButtonlink. You can learn some neat stuff about the 1-Wire protocol here.

wind, wind, go away

Ok yeah it's supposed to be rain - but our launch date just got scrubbed due to wind :( Note the projected path has the balloon landing in the Atlantic. Hrm, it's a bit chilly to be swimming.

Thanks to project SABLE folks who pointed out that our GPS was one that would not work above 60000 feet (oops). We ordered a new Garmin GPS (see parts list) to replace the Byonics GPS. Here is the list we found for GPS receivers that work at >60k ft.

We had another 2 crammed work days: setup up new GPS; soldered the new power connection to a DB-9 connector (for connecting GPS to RF transmitter); bought and setup a 2nd RF scanner; setup a 2nd laptop for 2nd chase vehicle; setup a spreadsheet to do all our math calculations (helium needed, ascent rate, burst altitude); tied ropes to connect parachute to cooler; punched holes through the cooler for the camera lens, antenna, and the GPS receiver; setup styrofoam shipping wedges to hold the camera in place in the cooler; created S- hooks with 90 degree turns to attach the ropes to the threaded rods on the cooler; and we've run a lot of simulations on ballon track with our spreadsheat numbers to decide if we should launch this saturday or not (tomorrow). For now we've scrubbed the launch. I suddenly have a lot more sympathy for why NASA is always moving the shuttle launches.

We've also decided that in hindsight, the parachute is too large. We don't need it to land like a feather - we just need the cooler and camera to survive. Our current payload estimate is 3lbs and our chute was rated for 3.5-8lbs (R7). We'll try to exchange the chute for a smaller one - maybe something in the 1.5-2.5lb (R3 or R4) range. Thanks to the folks at Rocketman for their advice here.

Software Recap

We are using several different bits and pieces of software for this project. We can split these apps up into a few different categories:

Pre Flight

• Ascent Rate & Burst Altitude calculator - This is a handy spreadsheet for calculating the ascent rate and burst altitude for your balloon. These numbers are needed in order for the tool below to calculate the balloon's flight path.
• Balloon Track for Windows is a software package that will project the flight path for your balloon. You tell the tool where you want to launch from, the ascent rate, the burst altitude, the descent rate and the wind data for your launch date and it models when and where your balloon should land. This is designed to give you a rough idea of where your balloon will go so you can avoid things such as your local airport and large bodies of water...such as the Atlantic Ocean :) If you have Microsoft MapPoint installed you can generate an image of the projected flight path. The green line shows the flight of the balloon during ascent and the red line is for descent. This shows us landing close to the ocean so we'll have to head west for our launch.

Payload

Our payload is pretty simple, we don't have an onboard computer so the only software application we are using is for our camera. CHDK is open-source 3rd party software that runs on several different digital cameras. We need to use CHDK to program our Canon A610 to take pictures on some set interval for an extended period of time. The default canon firmware has some time-lapse photography ability but it is limited to 100 pictures. We would like to take as many pictures as we can on a fully charged set of batteries thus the 3rd party software.

Chase Vehicle

• AGW Packet Engine - This is the software that listens to "line in" on your PC for the audio coming from your receiver. It translates the audio into a digital packet format that can be used by other windows applications.
  
• AGW Tracker then listens to the packets from AGW Packet Engine. These packets contain the GPS coordinates of our balloon which allows AGW Tracker to plot the location of the balloon on a map. If you have Internet connectivity you can just use google maps but if not you will need Microsoft MapPoint. We won't have Internet connectivity in our chase vehicle so we'll be using MapPoint.
  

Post Flight

• Google Earth - Free software (mostly) that will let you do some very cool stuff in terms of displaying the path of some object based on GPS data.
• GPS Visualizer - If you give GPS Visualizer a text file with the GPS coordinates of your balloon over time it can generate several different plots of the flight path. The best results are via a Google Maps image and a Google Earth file. Here is an example of a hang glider flight path in Google Earth:
• PixGPS - I haven't used this yet but PixGPS will let you tag your pictures with GPS coordinates in the EXIF data. This way you know exactly where the picture was taken which makes it possible for tools like Google Earth to display the pictures on a map based on where they were snapped.
  

What's Your Vector, Victor? Part Deux

The wonders of modern GPS systems are a huge part of this project. We're using Google and Microsoft Mappoint for our tracking software. (No, we didn't spend huge $$$ to get Mappoint. I got it free with my work volunteering for the National Girls' Collaborative Project, a pretty worthy cause that you should check out.) Google rocks, but we needed some sort of software that we could access without a connection to the Internet for map updates (like Google Maps needs).

Daniel took it out and drove around in his car the other day to see how the software works, and he was able to draw out a track (not shown here). Tonight, while we were waiting for Alli and Dale to come back from the store, Daniel came out front with the laptop and I rode off on my bike. (Kids, don't try this at home! Especially not after dark, in dark clothes, without a headlight. I should have been wearing sunglasses, too.)

Unfortunately, the antenna on the receiver wasn't powerful enough. We switched out the antenna (more power!) and then Alli and I went for a walk around the neighborhood.

Success! Here's a copy of the track we walked after it was imported to Google Earth. (It was actually dark out when we went walking.) We didn't actually walk *through* those houses, but it's pretty good for a homemade tracker system.

Perish the Thought!

And now, for something totally different... the chemical engineer is posting (instead of the three network engineers).

A lot has happened since the last post. Now we're working some on the mechanical engineering parts of the project: putting together the payload and connecting it to the balloon. A week ago Sunday, we made a trip to Lowe's to buy some of the nuts and bolts (literally) of the project. (When we figure out exactly what pieces end up as a part of the final project, we'll list them here.) We met at Dale's to work on building the payload.

We got a medical-grade styrofoam cooler, which came in a box like this one that Erin is modeling for us.

Dale and Alli drilled some holes into the cooler to push through two threaded metal rods, which were cut from a single 3-foot span. Unfortunately, the threads got crushed from being held in a vise to be cut, so we ended up breaking the rods and stopped for the day.

Transmit and Receive now working

We met at Dale's house last week to assemble and program our RF transmitter (the Micro-Trak 300). We programed the transmitter with our callsign and told it how often to transmit the GPS coordinates coming from the GPS Receiver. Programming the transmitter was done through a windows application from byonics.















We had to do a little bit of soldering...lucky for us Erin was there to give us a hand :) I suppose at this point she is destined to be an engineer.




















Here you can see how the power source, antenna, GPS receiver, and the RF transmitter all connect. We are able to receive the signal with our scanner, feed the audio output from the scanner into our laptop and have the laptop plot the location of the device on a map!