Arduino By Gordon McComb
The ArdBot is a low-cost, 7” diameter servo-driven robot base, ready for
expansion. It’s called ArdBot because it’s based on the popular and
inexpensive Arduino microcontroller board. The ArdBot costs under $80 to
build; even less if you already have some of the components, like the
breadboard, jumper wires, and battery holder.
In the last installment, we introduced the ArdBot and its central Arduino brain. This month, we’ll continue the discussion with full construction plans for the ArdBot. I built the reference design using 1/4”
expanded PVC plastic, but you can use wood, acrylic, foam
board, picture frame mat, or most anything else that is rigid
enough for the components.
ArdBot Basic Design
The ArdBot uses two “decks” for mounting a pair of
servo motors, batteries, microcontroller, small prototyping
board, and other components you’d like to experiment
with. The bottom deck is basically a 7” diameter circle with
cutouts for the wheels. The top deck is the same 7”
diameter circle with the side lobes cut off.
The decks are separated by a set of four 1-3/4” long
standoffs. The actual length of the standoffs is not really
important. You can make them shorter or longer — 1-1/2”
In preparing Part 1 of this series, I made a last-minute
change to include the new Ardunio board that's just been
released. Only I got the name wrong — in several places in
the article, I referred to the new board as the Duo. The
correct name for the board is the Uno.
52 SERVO 12.2010
is the practical minimum and 3” the maximum.
While it’s a bit more challenging to cut circles to make
a robot base, it’s the best overall shape for navigating tight
places like mazes or the corner of a living room. The
concept of the ArdBot is flexibility, however. There’s no
reason your version must be circular. You can make a
square bot if you’d like, or cut off the corners of the square
to make an octagon.
If you don’t want to construct the mechanical pieces of
the ArdBot at all, you can get them precut with all the
hardware; see the Sources box. ArdBot is designed for
expandability. If the twin decks do not provide enough
space for all your experiments, you can add more decks. I
don’t recommend any more than three decks total, as any
more may pose a weight problem for the drive system.
The brain of the ArdBot is an Arduino Uno — the latest
of the all-in-one core designs of the Arduino. If you already
own an earlier version of the board — a Diecimila or
Duemilanove — those will work, too. The only requirement
is that you have version 0017 or later of the Arduino
programming environment. The ArdBot project was created
and tested using version 0019 — the latest as of this
writing. Complementing the Arduino microcontroller board
is a mini solderless breadboard. It has 170 tie points —