8 SERVO 10.2014
Q. I am using an Arduino to control a small robot’s wheels with a 754410 motor driver chip. It uses ix pins to control the
direction and speed of two motors.
I’m using a lot of pins for other
things and wonder if there is a way
to use fewer I/Os to control this
chip (without adding more parts to
my board). Can you help me?
— Dave (via email)
A. There is hope for your quest o save on pins! At least a little bit of hope. The 754410
has two direction and one enable
for each of the two brushed motors
it can drive. If you use an I/O for
each, that is six digital outputs total. If, however, you
connect the two enable lines together so you enable both
by Dennis Clark
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t’s October and the month of the longest running "Battlebots" style competition in
existence: the Denver Area Mad Scientist's Club's Critter Crunch. I won't tell you how
long I've been participating in this competition (mostly because it's been so long I
don't remember), but I never tire of it, and my 13 year old son has now been
competing for three years himself. Actually, I have two months before the competition
and you won't hear about what happens until December — such is the magic of publishing!
Anyone in the Denver, CO area should check out MileHiCon ( www.milehicon.org) for the
schedule and drop by. Check out the MHC website for the rules to the Critter Crunch and
bring along a critter! Most critters are remote controlled, with some being so "old school"
as to have wired remotes to control them. So, it doesn't take much money or expertise to
field a critter. My Silver Surfer entry is one of only two regularly competing fully
autonomous robots in the event, so I'd welcome more! Any takers?
Anyway, this month I have a question about using an Arduino to control a motor driver
chip for a robot (is there anything you can’t do with an Arduino?). I was going to write
about a really cool LCD display system I've discovered, but it hasn't come in the post yet.
The streets in my area are under construction and the post office is too timid to risk the
900 foot trip to my driveway. So, when my postman gets up his nerve or I find my mail at
the local branch, I'll write something up on that topic later. On with this month's question!