26 SERVO 01.2010
Propeller Robot Control Board
The Propeller Robot Control Board from
Parallax features the
microcontroller and 64 KB
EEPROM, as well as the
components necessary to
interface with a PC, DC
motors, servos, sensors,
and more. With the same mounting hole placement as
other popular Parallax development boards, it is an easy
upgrade for existing projects.
The Propeller Robot Control Board provides all the
necessary base circuits needed to build a very powerful
mid-size robotics platform. The control board has an on-board USB serial interface to facilitate programming and
communication with the Propeller chip. A dual switching
supply regulates 6. 5 – 20 VDC input to 3.3V and 5V at up
to 3A, and contains green and red LEDs to indicate proper
operation or an under-voltage condition. The onboard
dual H-bridge motor driver makes it possible to directly
drive DC motors up to 2.8A and 20V. The 24 available I/O
pins are buffered through three eight-bit bidirectional
voltage level translators providing direct 5V interface
capability. The input voltage can come from a battery
pack or a wall adapter using a standard 2.1 mm barrel
The I/O pins are connected to three TXB0108 eight-bit bidirectional voltage level translators. They convert the
voltage from 3.3V at the Propeller chip to 5V at the servo
headers. These pins are fully bidirectional and are grouped
as three ports with eight I/O lines each. Each group is
brought out to a set of servo headers. A jumper selects
either 5V or VIN for the group. All data pins on the servo
header are at 5V signal levels, however should the need
arise to directly access the Propeller chip I/O for 3.3V
interfacing, solder points are provided to disable the
translators and gain direct access to the I/O pins.
The 64 KB EEPROM retains 32 KB for custom data
after a Propeller program is loaded. This extra memory
could be used for GPS lookup tables, map data, or
whatever the user decides. The USB interface provides a
serial connection to the Propeller chip through the USB
port of your PC. This interface is used for both
programming and communication with the control board.
Red and green LEDs indicate data flow between the
controller board and the PC. Price is $99.99.
Parallax’s new Sound Impact Sensor detects sound from up to
three meters away, lending noise activation possibilities to
projects. This sensor also includes an onboard
potentiometer for easy adjustment of the range of
detection for the sensor. This sensor is compatible with all
Parallax microcontrollers and sample code for both the
BASIC Stamp 2 and the Propeller chip can be found on
the Parallax website. Price is $7.99.
• Detection range up to three meters away.
• Onboard potentiometer provides an adjustable range of
• Single bit output.
• Three-pin SIP header ready for breadboard or through-hole projects.
• Built-in series resistor for compatibility with the Propeller
microcontroller and other 3.3V devices.
For further information on these two items, please
Pololu Micro Maestro Six-Channel USB Servo Controller
Pololu announces the release of the Micro Maestro, the first of its new line of USB serial
servo controllers. In addition to a
TTL serial interface, this tiny
board incorporates native USB
control for easy connection
to a PC and
programmability via a
simple scripting language
for self-contained, host-controller free applications. The
Micro Maestro’s extremely accurate,