I was  interested in connecting the [Arduino Yún] to a motor shield or a Zumo, so I contacted Adafruit, Arduino.cc and Pololu, the latter makes the Zumo to get some help. Here's a summary of what I learned.


! On connecting a Yún to a Zumo robot

I contacted Pololu about connecting a Yún to their mini Zumo robot. The
Zumo acts as an Arduino Shield, plugging right into the top of the Zumo.
It's designed for an Arduino Uno or Leonardo and the issue is that the
Yún gets its power via the "Vin" pin and that power **must** be a 5 volt
regulated supply — much higher and you'll burn out the Yún. This is
described, along with a solution, below. ~[This is included here with 
permission.]



%%blockquote
Hello, Murray.

Thank you for your interest in our Zumo robot.  The Zumo shield supplies 
7.45V to VIN, so you cannot use the shield in its default configuration 
to power a Arduino Yún Rev 2.  One way you could work around this is by 
cutting a trace on the bottom side of the board (the side with no 
components).  I attached a picture showing where to cut if you go that 
route (red line).  Then you would need to connect a regulated 5V source 
to one of the pins in I put a green box around or to the 5V bus.

If you want to avoid cutting traces, another option would be to keep the 
VIN header disconnected.  If you get the unassembled kit version of our 
Zumo for Arduino, you could just not solder a header pin to VIN.  If you 
get the assembled kit, you could just cut that header so that it does 
not make a connection when you attach your Arduino.  In either of those 
cases you would need to connect a regulated 5V source to the 5V bus.  In 
this case, make sure you do not connect your 5V source to any of the 
pins on the VIN bus!
 
For a 5V source, you might consider one of our 5V step-up/step-down 
regulators, such as our S7V7F5:

   [https://www.pololu.com/product/2119|https://www.pololu.com/product/2119] 

I recommend powering your regulator from VBAT; there is an exposed VBAT and GND pin you might use next to the Pololu logo.

Please let me know if you have any further questions or concerns.

 \\ Sincerely,
 \\ Patrick Messimer
 \\  [www.pololu.com|http://www.pololu.com/] 
 \\ ..............................
 \\ Pololu Corporation
 \\ 920 Pilot Rd.
 \\ Las Vegas, NV  89119
 \\ USA
%%
[{Image src='attach/ArduinoY%C3%BAnInterfacing/pololu_2508_trace_to_cut_to_disconnect_vin-thumb.jpg' link='attach/ArduinoY%C3%BAnInterfacing/pololu_2508_trace_to_cut_to_disconnect_vin.jpg' caption='Zumo Modifications (click to enlarge)' align='right' class='imgFloatRight'}]