shied away from all microcontroller support.
Remarkably, BEAM robots are not brainless, in spite of
their lack of coded behavior.
Recalling our quick review of the insect’s central
nervous system earlier, we can see that focusing on the
neuromeres or segment ganglia might be a great candidate
for guiding us in the design of a robot brain. These
segmented or metameric ganglia are ideal for mimicking in
a code-less controller circuit.
‘Hold on there,’ you might say. Isn’t this the domain of
BEAM robotics? Well, yes and no. Yes, BEAM designs tackle
many of the sensory and motor I/O behaviors that are
equivalent to a grasshopper’s neuromere, for example. But,
no, a BEAM circuit isn’t really suited for (nor was it
designed for) handling every possible robot configuration
with one circuit. For example, a solar-powered BEAM bot
would be pretty useless in the dark.
Rather, we can try to emulate an insect’s metameric
ganglia with a handful of discrete electronic components
along with, maybe, a digital IC or three.
No microcontroller is needed. Therefore, no coding will
be necessary for this robot brain. Also, remember this is not
a BEAM circuit nor is it intended to be a BEAM
replacement. It is merely a robot brain alternative to using a
microcontroller. And I call it Microcerebrum.
At the very heart of building this better bot brain is
CMOS. Complementary Metal-Oxide-Silicon or CMOS ICs
are thin sandwiches of positive (PMOS) and negative
(NMOS) channel MOS transistors that consume small
amounts of power from modest (i.e., 3V to 12V) power
supplies. By the way, low power consumption is an
excellent trait for any robot brain.
Furthermore, a CMOS IC plays well with discrete
components, as well as TTL/LS ICs (Transistor-Transistor
Logic/Low-Power Schottky; that’s the same kind of IC —
74HC240 — used in Mark’s Bicore BEAM robots). Likewise,
CMOS ICs come in a dazzling array of configurations and
logic patterns. Those two attributes are perfect for trying to
42 SERVO 11.2015
Figure 3. A schematic drawing of Microcerebrum.
