RFDuino is tiny low cost Arduino compatible board with wireless enabled microcontroller. It runs Arduino code and can do everything an Arduino can. Using the RFduino USB shield, simply plug the RFduino into a USB port of any computer and use the Arduino IDE to load your Arduino sketch, which automatically begins running on the RFduino. Then you can detach the RFduino USB shield and plug the RFduino directly into your project. No need to learn any new programming language or environment
The project used Nordic 32 bit ARM Cortex-M0 processor instead of AVR. The RFduino GPIO lines supports Digital IO, Analog ADC, SPI, I2C, UART and PWM. The RFduino has Bluetooth 4.0 Low Energy built-in, which enables it to wirelessly talk to any smartphone that has Bluetooth 4.0. The project comes with open source apps built for the iPhone (Open source Android apps are under development).