ing and eviscerating their parents old Kadettes and Clubs. Solid
electronic blocks replaced the radio sets messy innardsso where once you
could learn by tugging at soldered wires and staring into the orange glow of
the vacuum tubes, eventually nothing remained but featureless ready-made
chips, the old circuits compressed a thousandfold or more. The transistor, a
microscopic quirk of silicon, supplanted the reliably breakable tube, and so
the world lost a well-used path into science.
James Gleick,
Genius: The Life and Science of Richard Feynman
[1992]
Electronics lies at the center of much of technology of our times. We find
ourselves surrounded by ever more powerful and, in many ways, ever more
complicated and mysterious electronic gizmos and gadgets. In spite of the
central role that these devices often play in our lives, the inner workings of
these black boxes are almost completely hidden from view and are often
poorly understood by their users. Electronics is typically viewed as a
formidable subject that is best tackled by expert practitioners.
1
Why is it that most people view the subject of electronics as inaccessible and
esoteric? Well, for starters, the electronic world is inherently a more abstract
and less familiar one than, say, the mechanical world. We interact with the
mechanical world directly with our senses, which has lead to a multitude of
ways in everyday life for us to play with mechanical ideas, building with
blocks or taking apart a car engine for example. There have never been
many good opportunities for novices to play with electronics, but in recent
times the situation has gotten noticeably worse. The ever increasing
complexity of our electronic devices has served over time to diminish the
depth of our experience with the inner workings of the electronic world. In
the days before the coming of solid state electronics and integrated circuits,
one could more easily look at a circuit and see how the electron stream

1


Even among the technically minded, one finds a surprising amount of
discomfort with even relatively simple electronics. For example it is
striking how often in casual conversation working scientists will volunteer
that they feel under prepared in their knowledge of electronics. Electronics For Everyone
Page 2
flowed. Over the decades the capabilities of our electronic technologies may
have progressed at incredibly rapid rates, but our access to good ways to for
non-experts to creatively play with electronic circuits and ideas has lagged
far behind. For a young Richard Feynman, the process of tinkering with a
broken radio could serve as an ideal playground for exploring electronics
(and also act as a launching pad for making connections to other scientific
ideas). But for the present age of digital electronics, few comparable
experiences beckon.
The standard treatments of electronics in books or the curriculum are often
too formal and theoretical. Or they adopt the style of a cookbook, providing
recipes for constructing interesting electronic gadgets, but not aiming to
provide a deep understanding of the underlying principles. By only
constructing circuits that have been designed by others, readers miss an
important opportunity to learn the art of debugging a flawed design. In either
case these approaches fail students along a critical dimension; they typically
do not bring most to the point where they are able or even want to design
their own electronic circuits or build their own electronic inventions.
In most of the standard introductory electronics experiences the devices
being constructed often do not have a particularly compelling use. Typical
are bulbs and batteries exercises, in which students use a kit consisting of
a few batteries, flashlight bulbs and wires to build and explore simple dc
circuits. While the underlying ideas that are in play here (e.g. series vs.
parallel circuits, Ohms Law, short circuits, etc.) may be accessible at a
fairly early age, it is hard to see how someone would be inspired to extend
this kind of activity into a long term project. The remarkable electronic
gadgets that surround us in the world today raise expectations to a very high
level. Kids are bound to be somewhat disappointed with an exercise that
results simply in turning on a flashlight bulb.
Introductory electronics books and kits usually adopt a bland style that
appeals to a narrow segment of geeky hobbyists. To see what the client base
for these books and kits looks like, just walk into your neighborhood Radio
Shack and check out the customers, particularly the group hovering in the
electronic components section: The group tends to be overwhelmingly male
and the projects that are highlighted represent only a small range of the
possibilities. (One telltale symptom: Few if any craft materials appear in the
books.)
But this need not be so. With a more eclectic set of sample projects and a Electronics For Everyone
Page 3
more imaginative exposition there are many more people who would
become fluent designers and creators of electronic inventions. For example,
there are many ways to make connections to the arts community by using
electronics to create interactive art.
If the important and powerful ideas of electronics

are to be more widely
accessible, new tools and new methods are needed. We envision an approach
that is playful in spirit while still seeking to engage learners in the deep
underlying principles of electronics and the broad connections of these ideas
to other areas of engineering and science.
LogoChip: A new electronic construction kit
Paradoxically, the same microelectronic technologies that have contributed
to the black-boxing of modern electronic circuits can also be used as the
basis for a new kind of construction kit that will help reintroduce a
vigorously creative and playful dimension into the design of electronic
inventions. The basic building block that we have developed for this kit is an
easily programmable and inexpensive embedded microcontroller called the
LogoChip. Users can develop programs using a special version of the Logo
programming language on a desktop or laptop computer and then download
these programs to the LogoChip. LogoChip Logo combines all the power
and elegance of the Logo programming language with the ability to directly
configure and control the individual pins on the LogoChip.
A schematic for the LogoChip hardware is shown in the figure below. Electronics For Everyone
Page 4
2
-
PORTA0
3
-
PORTA
1
1
-
MCLR
4
-
PORTA
2
5
-
PORTA
3
6
-
PORT
A4
7
-
PORTA
5
8
-
Vss
9
-
CLKIN
10
-
CLKOUT
11
-PORTC0
12
-PORTC1
13
-PORTC2
14
-
RC3
RC4
-
15
RC5
-
16
RC6/TX
-
17
RC7/RX
-
18
Vss
-
19
V
DD
-
20
PORTB0-
21
PORTB1-
22
PORTB2-
23
PORTB3-
24
PORTB4-
25
PORTB5-
26
PORTB6-
27
PORTB7-
28
+5V
+5V
10k
+5V
20 MHz resonator
red/green indicator LED
Start/Stop Button
330
LogoChip Hardware
1
2
3
To PC's Serial Port
Figure 1 LogoChip Hardware. Pins shown in black can be configured by
users as digital inputs or outputs. (Port A can also be configured as an
analog inputs.)
The LogoChip is based on an inexpensive ($3) PIC microcontroller that has
been programmed with a virtual machine implementation of Logo. A user
would typically construct the LogoChip hardware on an electronic
breadboard by connecting the PIC to a small number of external parts: a
resonator that acts as a system clock, a button to start and stop program
execution, and a bi-color LED which serves as an indicator of the machines
current state. A cable connected between the LogoChip and the serial port of
a personal computer allows Logo programs composed on the PC to be
downloaded onto the LogoChip. Sixteen LogoChip pins (shown in black in
figure 1) can be configured by users as either digital inputs or outputs. Five
of these pins can also be configured as analog inputs.
The idea of providing a high level language interface to a microcontroller is
certainly not new. The popular Basic Stamp, for example, does exactly this.
But there are important syntactic and stylistic differences between the
LogoChip environment and existing environments like the Basic Stamp.
Logo programs have a structure more like natural language. Programs
written in Basic tend to be

less structured and hence less readable and harder
to follow than Logo programs. Another difference, admittedly more Electronics For Everyone
Page 5
subjective and harder to quantify, is that Logo programs have a style that
tends to be softer and more playful than Basic programs. The LogoChip
environment also features a command line user interface, so that users can
immediately test out the effects of modifications to the program. The
LogoChip hardware will also be significantly lower in cost (by a factor of 5
or more) and therefore potentially accessible to a much wider audience than
the Basic Stamp. (See the section entitled Fast, Cheap, and Out of Control:
Self-Replicating Hardware, Decentralized Distribution below.)
But more important than differences in the style of the LogoChip technology
are differences in the style of the LogoChip projects that we plan to develop
and encourage. A LogoChip based construction kit provides a low threshold
for novices to get started on interesting projects. In these starter projects the
emphasis is on small, simple and understandable additions to the LogoChip;
not on adding lots of specialized components that hide a lot of their internal
goings-on
.
For example one might start by plugging a LogoChip directl