Near Space Horizon

(Click on image to see a larger image)

This is my first attempt to limb sound from near space. These images were taken every 10,000 feet and stitched together. I tried to select the best, where the camera was pointed in the same direction. As you can see, they don't all line up properly, but it is a start.

In the future, I'll fly a sun sensor to let the flight computer align the camera properly. I also need to calibrate the field of view of the camera so the horizons can be properly aligned in the images (the horizon is depressed in near space - my photo montage assumes the horizon is not).

I'll put an article together for Nuts and Volts on this line of work. I assume it will be useful for detecting haze layers, including volcanic ash, in the future.

CheapBot Radio Antenna

Today I'm planning to solder the antenna for the ChepaBot radio controller. I purchases a SMA to SMA extension cable from Jameco for this. I'll cut the coax cable in half, peel back the inner conductor adn outer jacket, and solder wires to them.

The radios opewrate at a frequency of 434 MHz. If I take that frequency and divide it into 486, I get the proper length of the antenna (which will be a dipole). That comes out to 1.078 feet, or 12.936 inches. Divided in half and I get each element should be 6.5" long.

You can find an antenna calculator at http://www.crompton.com/wa3dsp/hamradio/antcalc.html

RC for Robots

I'm soldering a test board for a robot radio. To use it, you program a robot to respond to one of eight messages sent by the hand controller. The robot has its own radio and will reply back to the messages you send it. The handheld controller will have an LCD so human readable messages can be displayed.

The hand controller communicates with your robot like we communicate with rovers on Mars. Messages sent to the rover are acted upon, but intelligently, not as an automatic reponse like an RC car. That way, if you send a message to drive off a cliff, the robot can analyze your message and refuse to comply. Not only will it refuse, it will also send a message back about why it isn't complying.

Robotic Arm

I'm working on a simple robotic arm design for the CheapBot robots. It uses two servos, one to lift the arm and the second to pul a wire lasso tighter. The wired lasso is made from piano wire, so it naturally wants to spring open when the smaller servo extends the wires. Both ends of the wire lasso attach to the servo horn, so when it moves the ends of the wires one inch, the lasso expands by two inches.

I want to try a thinner wire. To make it simple to use, the lasso must be really flexible to wrap around the target regardless of how sloppy the positioning between the arm and the target is. The wire lasso also keeps the end of the arm very light, an important issue when you have a six inch long arm (you can build up a lot of torque for the servo to lift).

Rubber stoppers take out some of the slop in holding the target. I need to find a lighter weight "cushion" for this purpose and an easy way to mount it. I'll look into a foam rubber shirt for the end of the arm as a replacement.

I'll post some pictures soon.

NearSys 09G and H

Here are some images taken on last Saturday's mission.


This one was taken shortly after balloon burst. From around 80,000 feet, we're looking at the cloud cover over Melvern(?) Lake.

We're getting closer.....

Webpage Updates

I've started posting updates from the last near space mission. I'll massage some of the student Balloonsat data, but want to let them work their data over before I post the results.

Since it was two flights, there are two webpages for the results.

http://nearsys.com/arhab/flightdata/2009/g/index.htm
and
http://nearsys.com/arhab/flightdata/2009/h/index.htm

The only bad thing to happen was nylon zip ties failing and dropping one of the trackers (it's battery was dead by then). So it looks like I'll start some testing of zip ties in cold temperatures to see what I can learn from the experience.

The Ft. Collins Balloon Story

I helped launch two weather balloons this weekend. They were for Univeristy of Kansas and Kansas Wesylan University students. Some of these students will become science teachers and because of this experience, they will launch BalloonSats for their students.

However, after listening to the Balloon Boy story out of Fort Collins, I can't help but wonder if this is going to impact amateur near space exploration. All it takes is for one irresponsible person to negatively change public perceptions of amateur science in general and near space ballooning in particular. If as a result, access to near space ballooning is stopped or limited, students who's only dream is to launch experiments into space will be denied the opportunity of reaching this dream by taking their first step into near space.

Gawker is carrying an expose on Mr. Heene from a former friend and it doesn't cast a favorable light on him. I can understand Mr. Heene's concern if the balloon got away from him and he wanted to get it back. That however, does not excuse reporting that his son was onboard as a way to get state and federal government to track it. Claiming your son is onboard also reflects a lack of forethought. What are you going to say once the balloon is recovered (and it will) and its discovered no one was onboard?

I hope the public realizes Mr. Heene is not the face near space exploration.