Aug 17, 2018
Ed Meyer, physical chemistry experiments with Atari
computers
In the 1990s, Ed Meyer was a professor at DePaul University in
Chicago, where he taught physical chemistry. In August 1990, The
Journal of Chemical Education published his article, "An
Inexpensive Computer Station for Undergraduate Laboratories Using
the Atari 800XL" in which Ed showed how to interface the Atari
controller ports with a 12-bit analog-to-digital converter chip to
do chemistry experiments. (The article includes schematics and code
in assembly language and BASIC.)
From the article:
"The kind of “interfacing” that has been emphasized in
chemical education thus far in this country has been
largely
limited to using the “game paddle inputs” of a home com-
puter, which allows the connection of any device that
looks
like a variable resistor to the computer. This approach
has
served admirably as an introduction to the power and
versa-
tility of inexpensive home computers as data collectors
and
handlers but suffers from significant disadvantages. The
most obvious is the limitation to 8 bits of information;
one
would like to be able to obtain better precision than
this
provides (at half scale we can expect roughly 1%
reproduc-
ibility). Another is the requirement that the resistance of
the
transducer used be consistent with that of the game paddle
it
replaces.
It is possible, without spending inordinate sums of
money,
to convert one of these home computers into a research-
grade instrument with a resolution of 1 bit in 4096, if
one
knows a little about digital electronics. This article
describes
an interface for the Atari 800XL computer based on a
12-bit
analogue-to-digital converter (ADC). We have
incorporated
six of them into “computer stations” in our upper track
freshman laboratory. In general, the variables in
question
(e.g., temperature vs. time for coffee cup calorimeter
experi-
ments, pH vs. volume titrant) are plotted in real time on
the
monitor screen, and after collection of the data, a hard
copy
of the plot is produced on a printer, along with a table of
the
data. We use similar stations in our physical chemistry
lab-
oratory, where more sophisticated curve-fitting routines
are
included."
This interview took place on July 9, 2018.
"Once the thing is able to read a DC voltage, you have all
kinds of opportunities. ... I mean the most obvious one is to use a
pH meter to do acid-base titrations."