I am using the Nordic BLE shield with the TinyDuino. I've adapted the code in the "NRF8001_Nordic_BLE_Basic_Tutorial" from your website. On the master side, I am using either an iPhone or an iPad with the app "Bluefruit" from Adafruit.  The whole thing essentially works.  I'm generating data on the TinyDuino and successfully sending it over to the iPhone, where I display it.  I can also send data from the iPhone to the TinyDuino and have it react as I have programmed it.  The problem is that when I run the TinyDuino on battery power (disconnected from USB/computer) then the Bluetooth connection is lost within a minute or two.  On USB power, it goes on indefinitely (well, as long as the screen sleep mode is not invoked). 

The problem is basically with the button battery that I've been using.  I happen to have several TinyDuino's that run with the larger Li ion batteries sold by Tiny Circuits.  I tried one with the 290 mAh battery and now it works fine.  Maintained Bluetooth connection for many hours before I simply just stopped it on manually.  I'm not a Bluetooth LE expert, but my understanding is that in trying to conserve power it goes into low power mode when not transmitting or receiving.  Possibly the button battery cannot supply a surge current associated with the turning on ??  Or maybe there is another reason.