Nuts & Volts - July 2005

Near Space

• Spectra kite line (I use 50 pound test).

• Bearing swivels small enough to pass through a 3/16- inch tube (I use size 7).

• Split rings (one inch in diameter).

I only use the wooden needle point loops because I don’t know if the plastic ones are strong enough. The diagram in Figure 13 gives an idea of how I constructed my BalloonSat Carrier.

Start constructing the BalloonSat carrier by gluing the needle point loop’s inner ring into its outer ring with epoxy. Tighten the clamp in the outer ring and let the epoxy set. Afterwards, file the clamp off and fill the open gap with a small piece of wood. Drill three equally spaced holes into the loop (I use a Dremel tool with an 1/8-inch

Figure 13. BalloonSat carrier diagram.

JULY 2005

diameter drill bit).

Make the BalloonSat Linking Lines by cutting three lengths of Spectra kite line to a length of three feet. Melt the ends of the Spectra to keep them from fraying. Mark the Spectra six inches from the ends with a felt tipped marker.

Now, pass a length of Spectra through each hole in the needle point loop. Center the black mark in the hole and tie the Spectra into place with a knot. To make the knots secure, lay the end of the Spectra line along the rest of the Spectra and then tie an over-hand knot in the doubled-up section of the Spectra.

As long as the marks on the lines are centered in the holes of the needle point loop, the lines will be close to the same length after the knots are tied. Perhaps the diagram in Figure 14 will help explain how I tie a doubled over-hand knot (no doubt Boy Scouts reading this article can tell me the official name of this knot).

Mark six inches from the opened end of the Spectra line and use the same knot to tie a bearing swivel to the bottom end of each line. Do not use a snap swivel, as the snap can pull open during the more traumatic times of the flight (like balloon burst). You now have a wooden ring with three Spectra lines hanging down from it that are terminated in bearing swivels.

Look!

Finally,

Hands-on

Training for

PIC Microcontrollers

and PICBASIC PRO!

Introducing a Three-Day class of programming and hardware experiments designed to quickly bring you up to speed using PICs and PICBASIC PRO.

Come knowing nothing. Leave knowing everything you need to program PICs.

Coming to Chicago July 6-8, 2005. Check our web site for more details.

Each Student Receives: melabs PICBASIC PRO Compiler melabs Lab X1 Experiment Board melabs Serial Programmer RCG1 Experiment Board DC, Servo, and Stepper Motors LM34 and DS1620 Temp Sensors MAX7219 LED Driver LED and LCD Displays Relays and Solenoids AD8402 Digital Pot