nRF51822, in other words, Red Bear Labo's Nano board is supported by very useful Blynk. Blynk is quite handy environment which does not require smart phone programming but we can enjoy smart phone control. The following movie shows one example. (Also showing how OTA works with this module, we don't wire for binary uploading anymore!)
Also nRF51822 supports I2C and SPI and very popular SSD1306 OLED display can be driven by this tiny module.
Actual total current draw of BLE module and OLED is less than 10 mA and it can be supported by tiny CR2320 coin battery (I guess this does not last so long time, just for demo..)