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ANTIC The Atari 8-bit Podcast

hosts: Randy Kindig, Kay Savetz, Brad Arnold
twitter: @AtariPodcast
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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
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
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."
Article: An Inexpensive Computer Station for Undergraduate Laboratories Using the Atari 800XL
Heterogeneous catalysis