Servo - November 2010

or Freeduino to differentiate them from the original Arduino designs. The Adafruit Boarduino (available in kit form for under $18) is like the Arduino Nano. It uses thru-hole components for ease of soldering.

Some variations of the Arduino depart from the standard form-factor of the Uno, and are not designed for use with expansion shields (discussed below). A good example is the LilyPad — a special Arduino layout engineered for making (among other things) wearable microcontroller projects. Think Borg implants, only more friendly looking. The flower-shaped LilyPad has a flat profile and can be sewn into fabric. It has connection points on the ends of its 22 petals.

With so many variations of the Arduino floating around, it’s easy to get confused. For the ArdBot, we’ll be using an Arduino Duo, but you can readily substitute just about any of the other versions. If you already have an earlier Duemilanove or even Diecimila, you can use it with the ArdBot. The only catch is that you’ll need to make sure you have an up-to-date Arduino programming environment installed on your computer. I’ve tested everything with version 0019 of the Arduino programming IDE (discussed later), so with that version or anything later you should be good to go.

Ready Expansion Via Shields

The Arduino is an example of the KISS principle. Its simple design helps keep costs down, and makes the Arduino a universal development board adaptable to just about anything. While there are more expensive specialty versions of the Arduino made for robotics applications, the basic board lacks connectors to directly attach to motors, sensors, or other devices.

The Arduino itself has no breadboard area, but it’s easy enough to connect any of the inputs or outputs to a small breadboard via wires. For an application like robotics, you’ll want to expand the Arduino I/O headers to make it easier to plug in things like motors, switches, and ultrasonic or infrared sensors.

One method is to use an add-on expansion board known as a shield. These stick directly on top of the core board designs (Uno, Duemilanove, and Diecimila). Pins on the underside of the shield insert directly into the Arduino’s I/O headers. Two popular expansion shields are the solderless breadboard and the proto shield; both provide prototyping areas for expanding your circuit designs.

Of course, you don’t absolutely need a shield to expand the Arduino. You can place a breadboard — solderless or otherwise — beside the Arduino, and use ribbon cables or hookup wire to connect the two together. This is the approach we’ll be using with the ArdBot described in this series of articles.

USB Connection and Power

To allow the easiest possible means of programming, the Arduino Duo and related core boards support on-board USB. You merely need to connect a suitable USB cable between the Arduino and your computer. The cable even provides the power to the board. The necessary USB drivers are provided with the Arduino software. In most cases, installation of the drivers is not fully automatic, but the steps are straightforward and the Arduino support pages provide a walk-through example.

Main Components

This is a selected list of North American sources for the main components for the ArdBot.

Arduino Duo or Duemilanove
Source Item or SKU
Adafruit 50
HVW Tech 28920 (Freeduino SB)
RobotShop RB-Ard-03
SparkFun DEV-09950

Solderless breadboard, 170 tie-points
Source Item or SKU
Adafruit 65
HVW Tech 21380
Parallax 700-00012
RobotShop RB-Spa-139

Continuous rotation servo (Futaba spline)
Source Item or SKU
Parallax 900-00008
Pololu 1248
RobotShop RB-Gws- 23
Solarbotics 36000
SparkFun ROB-09347