Page 297 - Robots Androids and Animatrons : 12 Incredible Projects You Can Build

Calculated lift
3
Weight of air 8.4 (0.0807 lb/ft ) 0.678 lb
3)
Weight of helium 8.4 (0.0110 lb/ft 0.0924 lb
Weight of Mylar material 3 oz, or 0.1875 lb
Lift 0.678 0.0924 0.1875 0.398 lb,
or 6.37 oz
Construction
Construction of the blimp is simple and straightforward. Essential
to the construction is being able to make a good heat seal. Cut a
small section of Mylar material from the large sheet to practice on.
Fold the small section of Mylar, shiny sides to the outside, dull sides
together. Set the iron to a medium heat setting. Keep adjusting and
testing the heat setting of the iron on small Mylar practice scraps
until you find the right temperature. Every time you adjust the tem-
perature of the iron, allow at least 5 minutes for the iron to stabilize
to the new temperature. If the temperature setting is too hot, the
Mylar material will melt and create holes. If the temperature setting
is too cold, the heat seal will pull apart too easily. A good heat seal
will not pull apart easily. Allow the Mylar material to cool for a
276 minute before you test the heat-sealed seam. Once you have found
the right temperature setting, write it down for future reference.
We will make a pillow-shaped blimp. Fold the sheet of Mylar material
in half (shiny side out). Heat seal the three open sides closed,
leaving a little space that isn’t heat sealed for a fill tube at the bottom,
1
and you’re finished. The heat-sealed seam should be / " to 1" wide.
2
CCD camera

The CCD camera provides the video from the blimp (see Fig. 14.3).
Naturally, weight is a consideration. This camera weighs a little
1
1
1
over half an ounce. The overall size is 1 / 4" 1 / " 1 / ". Light
4 8
sensitivity is 0.03 lux. Resolution is 430 TV lines. Output video is
a standard NTSC (1V pp) signal. The camera can be powered
from 9 to 12 volts direct current (VDC) maximum. The current
draw from the camera is approximately 100 milliamps (mA).
A 9V transistor battery can power the camera. The battery weight
(1.5 oz) is three times greater than the weight of the camera itself.

TV transmitter
There are a number of TV transmitter kits available. There are two
basic classes of transmitters. One type transmits the video and audio
Team LRN
Chapter fourteen