So I finally got started on my high altitude balloon launch that I’ve been meaning to get to for months! You can read about it the "About Project HAL" page, but here's another brief synopsis of the project.
I will be using a weather balloon to launch a payload to a very high altitude (around 30km up, which is 18.6 miles for you English unit lovers out there). That payload will contain a camera (maybe 2), GPS receiver chip, microprocessor, and a radio of some sort to transmit the GPS data back to my laptop on the ground. Also, 4 (approximately, that number could go up or down) G-class amateur rocket motors.
More details and progress report after the break
I bought the GPS chip + antenna and an Arduino board (Arduino will essentially serve the role on onboard computer). I found the following site really helpful in selecting the right GPS receiver: http://showcase.netins.net/web/wallio/GPSrcvrsvs60kft.htm. I purchased the receiver and antenna mentioned in note 11 (from inventekys, not Bill Brown), but I haven’t received/tested them yet, so I’ll comment on that later.
So step 1 (purchasing was step 0) of the project is getting the GPS to communicate with Arduino and then getting Arduino to communicate with the computer.
Step 2 will then be to buy wireless radios (I’m thinking I’ll need something in the 900 MHz ISM band, but I’m waiting to talk to the local amateur radio club to make sure I don’t do something stupid and buy the wrong thing), and place them in between Arduino and the computer (in step 1 Arduino is connected to the computer with a cable). This is basically a test to make sure the wireless system works.
From there, I’ll need to buy a still camera to complement my video camera, buy some build materials (wood and cardboard probably), figure out how the parachute system is going to work (right now I’m leaning towards a side-mounted housing that will deploy some preset time after the ignition command is given to the motors), put everything together and do an all up test with the rocket (i.e. not with the balloon) to verify all my systems. When I say all up test, I mean launch the rocket from the ground in the configuration it would be in when it launches from the balloon. That way I can test the GPS tracking system and make sure the cameras are working properly without it going too far.
Wow that’s a long post. Well, now I twiddle my thumbs and do homework until the GPS chip arrives. My goal is to have that functioning by this weekend, so stay tuned for another update!