While visiting with Freescale’s Eric Gregori at the recent Embedded Systems Conference he showed me the company’s new mechatronics board that can control as many as eight RC-model servo motors. The board comes as part of a package ($US 199) that also supplies four RC servos, leg mechanics and associated hardware, assembly instructions for a two-legged four-degrees-of-freedom walking robot, and user manuals. For more information, visit: www.freescale.com/MechBot. And read a 2-page data sheet at: http://cache.freescale.com/files/32bit/doc/fact_sheet/TWRMECHFS.pdf. An “expressive face” PCB in the kit gives you 12 touch pads and seven LEDs to experiment with. You can add other devices via open general-purpose I/O pins or via I2C, SPI, and analog-to-digital pins.
In April 2011, NASA and the Boy Scouts of America started a program that will let scouts earn a Robotics merit badge. To receive this badge, a scout must understand how robots move, sense their environment, and how to cause a robot to perform an operation. Scouts will require about 14 hours of work to meet the merit-badge requirements and during that time they will design a robot and demonstrate how it works. I can’t think of a better way to help interest young people in robotics and mechatronics. Perhaps the Girl Scouts will offer a similar program.
Back to the technical details… The mechatronics board provides an MCF52259 32-bit ColdFire processor with 64 Kbytes of RAM and 512 Kbytes of flash memory. A battery holder beneath the board holds four 1.5-volt AA cells that power the MCU and the servos. You can add a 3-axis 10-bit-resolution accelerometer board and touch-sensor electronics on an Xtrinsic daughter card, part no. TWR-MECH, $US 99. Freescale also sells an adapter ($US 25) for a higher-resolution 14-bit 3-axis accelerometer so you can do dead reckoning and run other advanced algorithms.
The mechatronics board works with other Tower boards that let you add peripheral and controller modules that connect to each other via standard “elevator” boards. For more information about the Tower System and compatible boards, visit: www.freescale.com/webapp/sps/site/homepage.jsp?code=TOWER_HOME.
To get people off to a quick start, Freescale lets them program the MCU in “RobotSee,” a scripting language much like BASIC. Download the RobotSee software at: www.robotsee.com/ and find documentation at: www.robotsee.com/robotSeeHTMLHelp.htm. RobotSee examples show you how to make the robot walk, talk, access various sensors, and even “read your mind.”
If you want to program in C or C++, use the on-board open-source background-debug mode (OSBDM) hardware and Freescale’s CodeWarrior Special Suite software tools. You must use the CodeWarrior Professional Suite to program the MCU with C++ code. Freescale provides a complete C CodeWarrior project with examples of how to make the robot walk and access its sensors. Have fun. — Jon Titus