FIGURE 2. Solderless breadboard wiring diagram for
connecting the servos and power on the ArdBot.
other electronics. The two decks are separated by
standoffs. Of course, you can also use most any other
desktop robot for this project, like the Parallax Boe-Bot.
The main requirement is that your robot sports a pair of
servo motors for scooting around the floor. Obviously,
you'll need to adjust the construction details accordingly.
Figure 2 shows the basic breadboard wiring for the
ArdBot. Three double-long male header pins act as
connectors for the servos and servo battery pack. Jumpers
connect the header pins to one another, and to the
Arduino. For the battery connection, clip off 3" from the
end of a 12" three-wire servo extension cable. Set the 9"
length to one side — you'll use it later — and solder the 3"
length onto the pigtail ends of the AA battery holder. Use
heat shrink tubing or insulating tape on all solder joints.
(This is all assuming the battery holder has 6" wires. If this
is not the case, you'll need to use a longer length of servo
Figure 3 depicts how to wire the servos to the
breadboard, and then connect the Arduino. Note the extra
components on the breadboard:
• The 47 µF tantalum capacitor aids in removing
voltage spikes caused by the servos starting and
Bumper Car Bots
With Leaf Switches
Leaf switches are like cat whiskers: Brush against
the leaf, and the switch contact closes. That's all your
FIGURE 3. How
to connect the
servos to the
to the Arduino.
robot needs to know when it's made contact. Two standard
leaf switches mounted to the front of your ArdBot let it
detect when it's bumped against something. With the
switches situated to the sides, your bot can determine if the
object is on the left or on the right, and so can steer
Figure 4 shows a pair of leaf switches mounted like
bumpers to the front of the ArdBot. You can find switches
like these at many online electronics outlets. They're also
FIGURE 4. Close-up view of the leaf
switches mounted on the front of the
ArdBot. The area of each switch is
enlarged by using the rubber tubing.
SERVO 08.2012 55