Here's a nice Digikey article describing Electric Imp and its benefits.

What is it?

This is a small (0.7 x 1.46 inch) breakout board for Murata's IMP003 Electric Imp module with an STM32F405 ARM Cortex M4F processor operating at 144 MHz coupled with a 2.45 GHz (20 MHz channels) Broadcom BCM43362 wifi engine. The processor has 130 kBytes of RAM for application code. The board has an Antenova A5887 chip antenna which offers excellent reception in the home and up to 100 feet range outside of it according to my simple tests. The board has a 450 mA 3V3 NCP161 voltage regulator (the wifi alone can consume 400 mA for short times) and is intended to be powered by a single-cell 4.2 V LiPo battery. All of the pins are broken out on the board including pin N, which controls the blue led of the on-board Lumex LX0404 rgb led; the red and yellow leds are reserved for module status indication and are not generally available to the user. There is an on-board 8 Mbit W25Q80BLUXIG SPI flash memory used by the imp to store configuration data but 576 kBytes (above address 0x70000) of the flash space is available to the user. There is a reset button and a Fairchild KDT00030 photoresistor for "blink-up" binding of the electric imp with a wifi network.

The LDO voltage regulator uses only 18 microamps (quiescent current) when the IMP is asleep (the IMP uses only 6 microamp in its quiescent state) and a small 110 mAH LiPo battery should last close to 100 days if the imp is awakened only periodically with a low duty cycle. While the 18 microamp quiescent current is very low for a linear low-dropout voltage regulator, switching regulators can achieve even lower quiescent currents at the price of increased cost and complexity. The latter approach is preferred for the absolute lowest power consumption. In the present design, I accepted a bit higher power consumption for a smaller, simpler implementation.

I moved the 3V3 port away from the antenna end of the board to improve RF performance and lengthened the board by 50 mils to allow the addition of another pair of ports near the Reset button; a 3V3 port to replace the one lost and a port for VBAT. The latter is useful in case add-on boards are used for sensors, displays or motor drivers that require either higher voltage, more current than can be supplied by the LDO or both. With a simple motor driving circuit composed of resistors and FETs, the IMP003 Development Board can conveniently control servos and other DC motors. In addition, a backup battery can more easily be added, although even a coin cell battery really doesn't fit on such a small board!

The chip antenna adds a bit to the board cost but the advantage in addition to superior wifi reception compared to the old pcb antenna design is that I used the same layer stack, matching components, and antenna as the impee-fcc003-ca RF reference design and this may allow use of Electric Imp's modular certification for FCC testing in the United States. Please contact sales@electricimp.com for specific details.

The imp can be programmed via an on-line IDE using the Squirrel programming language, not too very different from C++ (Arduino) and standard C. It is straightforward to port Arduino sketches to the IMP003 but there is a lot more capability with the imp using the agent/device paradigm which allows imp-based devices to be easily controlled by any connected Smartphone or laptop. The imp makes web connectivity and remote control easy!

Why did you make it?

As my projects have gained in sophistication I have come to appreciate the addition of connectivity in addition to processing power and a variety of peripherals modern controllers like the Teensy provide. I am working on different add-ons (like the nRF51 and ESP8266) for the Teensy that will provide its users with added connectivity.

Here is a device with even more processing power than the Teensy, plenty of useful peripherals and GPIOs embedded with a "just works" wifi engine that provides connectivity in a straightforward and easy-to-use manner. I just had to try it, and I'm glad I did. The IMP003 is designed and manufactured by Murata in collaboration with www.electricimp.com. The electric imp platform is designed to provide scalable wifi connectivity as well as an intelligent cloud-based agency for remote control.

I designed this breakout board so I could take advantage of this powerful yet easy-to-use technology. I made it as small as I could so I could fit it just about anywhere. Now I am learning to remotely control, well, just about any device I can connect to this board.

What makes it special?

Like all Pesky Products, this board is appallingly small, meaning it will fit most anywhere you need remote control while still offering the full power of a Cortex M4 processor with single-precision FPU and 22 GPIOs with all the expected peripherals including 2x SPI, 5x UART, 2x I2C, 7x PWM, 2x DAC, 10x ADC.

Order the board from OSH Park and assemble your own if you want to save some money. Or buy the fully assembled and tested board from me and see how easy it is to control your robot, quadcopter, or toaster from your smartphone!