altitude measurement for a kite

Archiver

Hello,
Does anyone have an idea on how to measure the altitude of a kite?
Is there some type rangefinder that I can build with a stamp?

thanks
chad

Archiver

> Does anyone have an idea on how to measure the altitude of a kite?
> Is there some type rangefinder that I can build with a stamp?

It's not as much fun as a Stamp project but Estes used to sell a small
optical type gadget that you could estimate height of rockets.

Tim

Archiver

At 23:05 02/24/02, bear_phillips wrote:
>Hello,
>Does anyone have an idea on how to measure the altitude of a kite?
>Is there some type rangefinder that I can build with a stamp?

A Stamp sounds like overkill, and would require a lot of supporting parts,
optical and electrical, to do a precise job.

For a practical measurement involving $1 in parts:

1. Get yourself a protractor and a piece of string with a weight on
it. Hang the string from the center of the straight edge of the protractor
and sight along the straight edge until you line it up with the kite, then
read the angle where the string crosses the marked divisions. Pace off or
otherwise measure the distance to a point straight under the
kite. Calculate the height as: Height = Distance x tan(angle). A GPS
unit is an option for measuring this distance.

or

2. If you know the length of the string to the kite, then you don't need
to measure the distance to a point beneath it. The height would
be: Height = Length * sin(angle). The string will sag a bit so the
string length will be a bit longer than the actual straight-line distance
from you to the kite. You can make an estimate of how much to subtract
from the string length for slightly improved accuracy.

The angle is the angle up from the ground, not the angle off
vertical. Most protractors have two sets of graduations, so choose the
correct one.


Jim H

Archiver

I wonder if you used say a 100 Hz square wave to modulate an IR. LED,
pointed that at a reflector on the kite then used a telescope to look at
it and focus it's light on an IR. transistor and used the stamp to
compare the pules width or this signal to the original signal? Would
that work or am I mixing up what a radar detector does??

Leroy

Jim Highness wrote:
>
> At 23:05 02/24/02, bear_phillips wrote:
> >Hello,
> >Does anyone have an idea on how to measure the altitude of a kite?
> >Is there some type rangefinder that I can build with a stamp?
>
> A Stamp sounds like overkill, and would require a lot of supporting parts,
> optical and electrical, to do a precise job.
>
> For a practical measurement involving $1 in parts:
>
> 1. Get yourself a protractor and a piece of string with a weight on
> it. Hang the string from the center of the straight edge of the protractor
> and sight along the straight edge until you line it up with the kite, then
> read the angle where the string crosses the marked divisions. Pace off or
> otherwise measure the distance to a point straight under the
> kite. Calculate the height as: Height = Distance x tan(angle). A GPS
> unit is an option for measuring this distance.
>
> or
>
> 2. If you know the length of the string to the kite, then you don't need
> to measure the distance to a point beneath it. The height would
> be: Height = Length * sin(angle). The string will sag a bit so the
> string length will be a bit longer than the actual straight-line distance
> from you to the kite. You can make an estimate of how much to subtract
> from the string length for slightly improved accuracy.
>
> The angle is the angle up from the ground, not the angle off
> vertical. Most protractors have two sets of graduations, so choose the
> correct one.
>
> Jim H
>
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Archiver

At 13:42 02/25/02, Leroy Hall wrote:

>I wonder if you used say a 100 Hz square wave to modulate an IR. LED,
>pointed that at a reflector on the kite then used a telescope to look at
>it and focus it's light on an IR. transistor and used the stamp to
>compare the pules width or this signal to the original signal? Would
>that work or am I mixing up what a radar detector does??

You're confusing speed detection of a moving object by measuring Doppler
shift with distance detection done by measuring round trip delay. The
Stamp isn't fast enough to handle either task directly.

An alternative response could have been: "I am NOT trying to be mean or
nasty, but if you can't use Google to look up the difference when you
suspect you might be wrong from the get go, maybe you should consider not
posting next time." But then that wouldn't have been at all constructive.


Jim H