Get the Most
Small, ready-to-use wireless modules let you control motor
speeds and actuators in robots. These inexpensive modules
also have other capabilities that engineers, experimenters,
and robot builders can take advantage of. The XBee Series-1
transceiver modules, for example, transfer digital and analog
information, create networks of modules, go into power-saving
sleep modes, and work with microcontrollers via a universal
asynchronous receiver-transmitter (UART) port. I'll provide
examples of how to use the XBee modules to help new bot
builders get off to a good start.
by Jonathan A. Titus
You can use XBee modules as bare-bones wireless serial communication links to transfer information back and forth, perhaps to control a remote device or to report the state of digital and analog inputs from
remote sensors. The XBee Series-1 modules that operate in
the 2. 4 GHz band have a maximum range of about 100
feet indoors and about 300 feet outdoors. The XBee Series-
1 PRO modules communicate over longer distances.
Each 20-pin XBee module provides seven digital and
analog I/O pins; one digital only I/O pin; one digital input
pin; and two pulse width modulation (PWM) outputs. Pins
for serial communications (UART), power, and control use
the remaining pins. The diagram in Figure 1 shows a top
view of the XBee pin numbers and signal abbreviations.
FIGURE 1. Pin locations, numbers, and
functions for an XBee XB24 Series 1 module.
44 SERVO 01.2013