This tutorial was extracted from Erich Styger blog http://mcuoneclipse.wordpress.com with his agreement.
The cool thing with the Freedom board is: there are many exciting Arduino boards out there which want to be used with the FRDM-KL25Z. I have spent most of my last week-end with creating a little black beauty:
FRDM Zumo Robot
When I was looking for some nice DC motors with quadrature encoders for my next lecture project, I stumbled over the Pololu web site which had *exactly* the DC motors I was looking for. And their Zumo Robot Robot Kit was something which attracted my eyes.
I always joked 
about women shopping habits. But my wife is right: If it is about electronics, I’m not different at all 
That robot is smaller than 10 cm on each size, so it qualifies as a Mini-Sumo. Although I have a different purpose in mind for my robot…..
Chassis and Motors
I ordered the chassis with two 75:1 Micro High Performance Metal Gearmotors which enable the chassis to move about 50 cm in a second. The chassis includes a battery compartement on the bottom for 4 AA batteries (so up to 6V):
Zumo Chassis with DC Motors
I did *not* follow the Pololu instructions to solder the motor with the Arduino shield: instead I used flexible wires to attach the motors to the board. That allows me to change motors or disassemble the kit in a much simpler way.
Arduino Board
The Arduino board comes with a few parts unpopulated (Buzzer, Headers, Switches). The board features a tiny (but powerful) Dual Full-H Bridge, a Buzzer, Battery Voltage Sensing and a I2C Accelerometer+Magnetometer sensor:
Zumo Arduino Board
Freedom Board
The FRDM-KL25ZFRDM-KL25Z needs to connected‘face down to the Zumo board I plan to layout an intermediate PCB with my to-be-added hardware But for now I’m using normal breakable header rows as‘interconnection This is necessary as otherwise the Freedom board is very close to the Zumo board components
Headers to increase distance between boards
Power Supply
The FRDM-KL25ZFRDM-KL25Z is powered from the batteries through P5-9VIN But the Freedom board only generates the 3.3V from P5-9VIN and but not the needed 5V to the header(see this post). That 5V is needed by the Shield. So for now I’m using a rather bulky DC-DC converter and supply the needed 5V from the battery to the USB 5V supply line, until I can replace the DC-DC converter with a smaller one. At least everything is working now 
.
Software, and Next Steps
The software in CodeWarrior with Processor Expert is ready for most parts. Motors (speed/direction), LED’s and Buzzer are working. Magnetometer/Accelerometer and Battery Voltage Sensing are in progress. The current software is available on GitHub with all the Processor Expert components. And: I have a Bluetooth module ready to integrate, plus I want to add a line scanning module too. So enough fun for a couple of dark nights and week-ends .
FRDM Zumo backside
Happy Zumoing