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Re: Apple ii projects for kids?
Sam Latella wrote:
Sam Latella wrote:
Hi,
Does anyone know of any good apple ii projects for kids be it software or
hardware based for the Apple IIe or IIgs.
Something simple but still has a learning potential about computers either
hardware or software.
We are thinking of this year's science far project and would like to show
case the Apple iie as the center piece, and give it a wow factor!
Basically a blast from the past!
Any ideas would be much appreciated.
Thanks,
Sam
Any real live train programs that actually control a model train set with
track and the whole works?
Trying to make this as an introduction to my 3 kids, so they can play with
an Apple IIe and IIgs and get a basic understanding of computers, and get an
idea for a science fair project.
As has been noted, the Apple II line (except for the //c and //c+) has
four TTL digital outputs, called "annunciators", on the internal 16-pin
game port connector. There are also three TTL digital inputs on this
same connector, called "pushbutton" inputs. (The IIgs adds a fourth,
"repurposed" from the missing cassette input.)
It is easy to set the annunciator outputs and read the pushbutton inputs
either in Applesoft or in machine language.
If they are used from BASIC, the speed of the language limits their
time resolution and speed, but if you can tolerate several milliseconds
of jitter in reading or writing, BASIC PEEKs and POKEs work fine.
If they are used from machine language, timing resolution is just a
few microseconds--a very substantial improvement, but only if you
actually need the speed or timing precision. (Digitizing audio
at the cassette port is an example requiring a short machine language
program for several kilohertz sampling speed.)
(BTW, I have a small Applesoft program on my website called
HEX DUMP READER which plays back cassette port digitized sounds.
It contains both the short machine language sampler routine and
the machine language playback routine. You might want to download
it and study it.)
For example, if you were using a pushbutton input (or even a paddle
"analog" input) connected to a CdS photocell for sensing the swing
of a pendulum, you could easily read its period to better than 1%
accuracy if the period was on the order of a second--a quite practical
pendulum for experimentation.
In general, the computer is easy to use as a data collection,
processing, and display device (using the monitor and hi-res screen).
Using the computer to control things like LEDs is pretty boring to
most people these days, who are accustomed to lots of winken-blinken
lights controlled by a tiny speck of silicon and a watch battery!
This is particularly so since the Apple II has a native capability
to control thousands of color pixels on its hi-res screen.
Perhaps the central question is: What are your children interested in?
To serve its purpose, a science fair should engage the imagination and
skills of a child, and not be a showcase for projects conceived and
constructed by parents.
Perhaps the best use of the Apple II would be to allow easy numerical
analysis of data collected by, say, looking at water samples with a
microscope.
If, on the other hand, your children are interested in computers and
programming, then writing a small program could *be* the project. The
barriers to learning programming these days are much higher than they
were on the Apple II, so it is a very appropriate pedagogical tool.
Again, the display and hi-res graphics provide instant feedback
without having to learn volumes of graphical interface details.
In a couple of dozen lines, one can write a program to plot a
function. A dozen or so more lines will add axes and a grid.
(Unfortunately, it's a little harder to add labels, but the bottom
four text lines can be quite informative.
Building hardware to attach to the Apple II has some risks--it's
not too hard to burn out the TTL inputs and outputs with careless
connections and ESD. If your children are careful, can solder or
use a breadboard, and have a basic understanding of electricity,
they may be able to create simple switch, thermistor, and photocell
interfaces for the Apple II. These will allow them to sense events,
temperatures, and light levels. (The paddle inputs--also available
at the game port--are a fine way to connect thermistors and photocells,
as long as their useful resistance is in the 30K-120K ohm range.
(You want their variations to be sensed with reasonable resolution.)
After all, a "paddle" is just a variable resistance ranging from
0 to 150K ohms. Electronics supply stores have thermistors and
Cadmium Sulfide photocells that operate in this range.
A switch and a resistor is all that's required to drive a TTL
input--the game port also has +5 volts for the high end of the
pullup resistor.
Annunciator outputs usually require buffering with a transistor
amplifier to control more than a few milliamperes of current,
but each buffer is just two resistors and a transistor--easy.
Although a parallel printer card can supply you with eight
TTL outputs, you can do plenty with just the four annunciators.
If you use one for a data output and another for a clock line,
you can cascade shift registers to create as many bits of output
as you like--particularly if you use a small machine language
program to rapidly shift the data out into the shift registers.
With four outputs and three inputs, you can trivially scan a
12-keyswitch keypad, like a telephone keypad--and you will
learn how to debounce switches by doing a confirmatory scan,
too!
An Apple presents virtually unlimited opportunities for learning
about digital interfacing, data processing, and display. Note,
though, that just a small change in aspirations can result in
timing constraints that make a problem very difficult (if not
impossible) on an Apple II. It is necessary to select time
scales and data volumes that are conveniently dealt with using
an Apple II.
So your real problem is that there are too many possibilities!
Have fun--and may your children have fun with it, too. ;-)
-michael
NadaNet 3.1 for Apple II parallel computing!
Home page: http://home.comcast.net/~mjmahon/
"The wastebasket is our most important design
tool--and it's seriously underused."