My setup has now been working fine now for about 2 months
Only thing I did was this
sudo apt-get update
sudo apt-get upgrade
When I posted before I forgot a few details of my setup
OSPi 1.4+
Raspberry Pi B+
EDIMAX EW-7811Un Wireless Adapter
Current OS is
Linux ospi 3.18.11-v7+ #781 SMP PREEMPT Tue Apr 21 18:07:59 BST 2015 armv7l GNU/Linux
This may be newer than I originally had, not sure
If you are still having issues you might want to look at these two blog posts on Disable Power Management for WiFi and/or USB
I have not done this. I was waiting on results first of apt-get upgrade, and its been two months without loosing connectivity
http://www.midwesternmac.com/blogs/jeff-geerling/edimax-ew-7811un-tenda-w311mi-wifi-raspberry-pi
http://www.raspberrypi-spy.co.uk/2015/06/how-to-disable-wifi-power-saving-on-the-raspberry-pi/
The idea being that you need to “CREATE” a file /etc/modprobe.d/8192cu.conf to disable the Power Management