On October 30, 2014 8:37:27 PM EST, Peter Gutmann <pgut001@cs.auckland.ac.nz> wrote:

mroq qorm <mroqorm@gmail.com> writes:
On Thu, Oct 30, 2014 at 3:21 PM, Tomasz Rola <rtomek@ceti.pl> wrote:
 USB condom, great name :-).
http://syncstop.com/ - there was an open hardware version of this somewhere,
but maybe all that went away when they got a new name and a hipster website
... not for the purpose you are discussing but still useful.

More generally, search for "charge only usb cable" and you'll find lots
of things like this, e.g:

http://www.ebay.com/itm/2M-6ft-LONG-THICK-Fast-Charging-ONLY-USB-Cable-WHITE-4-iPad-Air-2-mini-3-Retina-/291161982615?pt=US_Tablet_eReader_Chargers_Sync_Cables&hash=item43ca9b4697
http://www.ebay.com/itm/High-Speed-Charge-Only-Micro-USB-Charging-Cable-Android-Quality-Fast-Charger-/221266793926?pt=UK_MobilePhones_MobilePhoneAccessories_MobilePhoneChargers&hash=item33848755c6
http://www.ebay.com/itm/GYRRH-Micro-USB-Power-Charge-Only-Cable-3ft-91cm-Yellow-/131304066524?pt=US_USB_Cables_Hubs_Adapters&hash=item1e92550ddc

Something like this, $1.99 including shipping:

http://www.ebay.com/itm/Micro-USB-2-0-Charging-Charge-Only-Cable-For-Samsung-Galaxy-HTC-Nexus-Android-63-/111283024587?pt=US_Cell_Phone_PDA_Cables_Adapters&var=&hash=item19e8fc32cb

is great for carrying around for charging your phone when you're travelling, 
just mark it in some way so you don't get frustrated when you can't sync your 
phone with it...

Peter.