MANAGING YOUR
MOBILE MONKEY
by Fred Eady
PHOTO 1. The 2 GB microSD memory card fits neatly into an
automatic release microSD socket on the other side of the
uDrive-uSD-G1 printed circuit board. You may also use a 64 MB or
1 GB microSD memory card if 2 GB is overkill for your application.
As a robotician, think about all of the neat things that you have direct access to by way of the
pages of SERVO. For instance, Parallax offers a variety of sensors that include a PIR (Passive
Infrared) sensor, a color sensor, and a combination temperature/humidity sensor to name just
a few. Digging deeper into a SERVO magazine I’m reading at the moment reveals a company called
Maxbotix that is offering an ultrasonic sensor they call MaxSonar. If you want to sense with IR, you
have the resources of HVW Technologies at your disposal. As a reader of SERVO, you know that I’ve
just scratched the surface when it comes to innovative gadgets offered by SERVO advertisers.
Obviously, sensing and gathering data is a robot thing.
However, what do you do with all of those bits of information your little aluminum monkey finds? Sure, you may be
able to process most of it immediately but there may be a
time when you need to store the data bananas your mobile
metallic simian has gathered for analysis or use at a later time.
Most modest robotic designs are based on small
microcontrollers and as a rule, small microcontrollers don’t
pack a punch when it comes to available data SRAM. The
average PIC microcontroller can only promise about 3 KB or
less of on-chip data memory. If your application is based on
the new PIC32MX, you can count on a bit less than 32 KB
of data memory and that’s only if you use the largest
PIC32MX variant. You can also choose a PIC microcontroller
that will allow you to attach a big chunk of SRAM to its I/O
subsystem. If money is not an issue and your robot doesn’t
have a power, weight, or size limitation, you can choose to run
50 SERVO 05.2008
your robotic data collection agency with a full-blown Intel-based or AMD-based embedded computer and a regulation
spinning disk drive. Regardless of your robot’s size or power
source, would you be interested in reading the rest of this
article if I could show you how to add 2 GB of direct access
storage to your robot with a PIC and a micro-SD memory card?
uDrive-uSD-G1
My uDrive-uSD-G1 and its storage element can be seen
in Photo 1. As you can imagine from the view, the uDrive
and its micro-SD memory card are very compact and don’t
tip the scales to any great extent. It’s also apparent that the
uDrive is designed to be a holding tank for a very large
amount of data. The cool thing about the uDrive is that is
has a humongous data capacity and a very tiny I/O
interface. All you need are two I/O pins to facilitate
