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From software algorithms to material selection, Mr. Roboto strives to meet you
where you are — and what more would you expect from a complex service droid?
by
Dennis Clark
By now, First LEGO League’s qualifiers will be over and
our team will or will not be advancing. Since my crystal ball
is in for repairs, I can’t say how that will turn out, but my
fingers are crossed and the team is working hard. Getting
ready for a robot competition is a real ordeal for me and
time has flown. I end every competition with grand plans
for the next year ... a solemn vow to get started right
away. As usual I start working on the robot a month before
the next event. Sigh, I never learn. The world is full of
distractions, but there is always NEXT year!
I’m going to pick up where I left off last month
discussing Finite State Machines (FSMs) and creating the
illusion of multiple programs/functions/behaviors running
at the same time. I’m going to combine this discussion
with my love of hacking toys into robots. Since my
mechanical construction skills lag somewhat from my
programming and electronic skills, I like to use platforms
that someone else has already worked on to get everything
to hang together mechanically. The example platform I’m
going to use is an old spider that Wowee made several
years ago called the “Cyber Spider.”
If you can find one on eBay or at your local
thrift store, get one. It is supremely hackable.
Not long ago, I revisited this creation and added
some functionality that attempts to keep it from
walking off of a table top. It worked, sort of.
Sort of because it requires a rough table top so
that the IR beam doesn’t reflect completely away
from the robot. (Sigh, there are dreams and then
there is reality.) Regardless, the code from this
project shows very nicely how to get multiple
behaviors to work together and simulate an
operating intelligence in our mechanical marvels.
Onward!
Figure 1. High level FSM.
Figure 2. Wander FSM.
Our High Level FSM
(Finite State Machine)
Our spider robot has a couple of sensors and
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