THE GIGANTOR 555
I’d like to introduce you to the revolutionary GIGANTOR
555 Boe-Bot Shield. I designed the shield to use with
Parallax’s famous educational robot. It only has nine
components, but adds a very important capability to the
Boe-Bot. The shield flashes two jumbo LEDs and a beeper
which act as warning signals to young children and small
pets who may be in the path of the oncoming robot. Check
out the diagram in Figure 3.
As you know, I could have used a $0.50 555 IC to flash
the LEDs, but I was desperate to find an application for my
new 555 timer board. So, I mated it to the shield with some
old fuse clips. Figure 4 shows the Gigantor patrolling the
I did make one mechanical change to the legs in the kit
to make them compatible with the shield. I cut the left and
right legs apart into eight separate “pins,” then connected
each one to its respective electrical post. This allowed the
modified pins to electrically mate with the clips below (see
A NEW PERSPECTIVE
While the kit was fun to build, there was another
aspect of the 555 that I thought you might enjoy learning
about. A while ago, an inquisitive software engineer named
Ken Shirriff decided to look at the 555 from a completely
different perspective, i.e., microscopically. He took detailed
high-magnification photos of the various integrated
structures on an actual 555 silicon die using a special
microscope and explained the technical operation of many
of the functions on the chip. A link to his webpage and blog
can be found in the sidebar.
Ken has graciously given me permission
to use his microphotographs to illustrate how
the various components such as transistors
and resistors are constructed on the die. I’ve
taken the liberty of adding some annotations
to his photographs to help explain them.
However, I’m not going to delve into the
operation of the 555 because it has been
covered extensively in other places. My focus
will be mostly on the visual.
THE BIG REVEAL
First, Figure 6 shows the metal can
version of a bipolar 555 with its top
hacked off, compared to a penny. The little
rectangular silicon die is in the center of the
can and is about 0.063”wide, which is 1/16
of an inch. Pretty small.
Figure 7 is the big reveal: a highly
magnified color-annotated view of the
entire die. The black leads around the
outside are the eight wires that connect the
1. See “Ken Shirriff’s Blog” at www.righto.com for his
humongous site covering many interesting projects.
2. www.righto.co m/2016/02/555-timer-teardown-inside-
Figure 4. Autonomous Gigantor robot on patrol.
Figure 3. The discrete 555 timer mates with the shield using
modified fuse clips.
SERVO 09/10.2018 59
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